260 — 14 August 2014 Editor: Bo Reipurth (Reipurth@Ifa.Hawaii.Edu) List of Contents

Home , 25 Orionis, HD 169142, HD 41004, HK Tauri, Homunculus Nebula, NGC 7538

THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 260 — 14 August 2014 Editor: Bo Reipurth ([email protected]) List of Contents

The Star Formation Newsletter Interview ...... 3 My Favorite Object ...... 6 Editor: Bo Reipurth [email protected] Perspective ...... 12

Technical Editor: Eli Bressert Abstracts of Newly Accepted Papers ...... 17 [email protected] Meetings ...... 56 Technical Assistant: Hsi-Wei Yen New and Upcoming Meetings ...... 58 [email protected] Short Announcements ...... 59

Editorial Board

Joao Alves Alan Boss Jerome Bouvier Cover Picture Lee Hartmann Thomas Henning The cover shows the W5-NE region, a bridge of Paul Ho molecular cloud separating the HII regions/clusters Jes Jorgensen W5-W (IC 1848) and W5-E (AFGL 4029). The im- Charles J. Lada age is about 12 × 14 arcmin, corresponding to ap- Thijs Kouwenhoven proximately 0.11 × 0.13 pc at the assumed distance Michael R. Meyer of 1.95 kpc. The bright star at the center of the im- Ralph Pudritz age is BD +60◦596, a B1V star which has created Luis Felipe Rodr´ıguez the cavity seen in the image. Numerous young low- Ewine van Dishoeck mass stars are found in this region, including the Hans Zinnecker young variable LW Cas. East is up and north is right in this image. The Star Formation Newsletter is a vehicle for fast distribution of information of interest for as- Image courtesy Ken Crawford http://www.imagingdeepsky.com tronomers working on star and planet formation ( ) and molecular clouds. You can submit material for the following sections: Abstracts of recently accepted papers (only for papers sent to refereed journals), Abstracts of recently accepted major reviews (not standard conference contributions), Dis- sertation Abstracts (presenting abstracts of new Submitting your abstracts Ph.D dissertations), Meetings (announcing meetings broadly of interest to the star and planet for- Latex macros for submitting abstracts mation and early solar system community), New and dissertation abstracts (by e-mail to Jobs (advertising jobs speciﬁcally aimed towards [email protected]) are appended to persons within the areas of the Newsletter), and each Call for Abstracts. You can also Short Announcements (where you can inform or re- submit via the Newsletter web inter- quest information from the community). Addition- face at http://www2.ifa.hawaii.edu/star- ally, the Newsletter brings short overview articles formation/index.cfm on objects of special interest, physical processes or theoretical results, the early solar system, as well as occasional interviews. Newsletter Archive www.ifa.hawaii.edu/users/reipurth/newsletter.htm

2 the launch of IRAS. So we missed out on jets/disk winds, though I think our paper did provide some motivation for Lee Hartmann the X-wind model of Frank Shu and his collaborators. in conversation with Bo Reipurth The Alfven wave-driven wind models were also motivated by the need to produce massive flows in the absence of significant thermal and radiative driving, but in this case the stars were known to be slowly rotating, so we had to invoke high-frequency, turbulently-produced waves. Work- ing first with Suzan Edwards and Gene Avrett, and then later with Nuria Calvet in the context of schematic disk winds, we could get emission line ratios fairly well, but the line profiles generally didn’t match the observations. Then in 1989 I was visiting Santa Cruz and mentioned the problem of the slow rotation of T Tauri stars to Doug Lin. Doug suggested that the slow rotation was a result of magnetospheric coupling which transferred excess stellar angular momentum to the disk. Cluelessly, I dismissed this idea because I thought making a magnetospheric hole in the disk should produce a gap in the near-IR infrared Q: Your early papers had nothing to do with young stars. spectral energy distribution that was not apparent... just How did you develop your interest in star formation? before Arieh Königl’s paper came out on magnetospheric A: My early years were really kind of a random walk braking. (My mistake was to ignore emission from the through (mostly) stellar astrophysics. I worry a bit now directly-illuminated, hotter inner “wall” of the dust disk, about young people who don’t have the opportunity to which fills in the short-wavelength SED, as shown by An- try out different things until they find the subject that’s tonella Natta and collaborators.) I went back to Nuria best for them. Anyway, I had originally been working on and said, we’ve gotten this all wrong; we should be doing the theory of extended stellar atmospheres and winds as a models of (magnetospheric) infall, not outflow. Making grad student with Joe Cassinelli at Wisconsin, but decided this change resulted in very good agreement with many I needed some observational experience and worked with line profile observations, as ultimately developed in some Chris Anderson on spectra of flare stars. The resulting detail in James Muzerolle’s thesis work. thesis wasn’t very good but it introduced me to solar-type Q: Your first venture into observations of young stars magnetic activity. came with your 1982 paper on high resolution spectroscopy Then I went to CfA as a postdoc and began working with of T Tauri stars. Another large observational effort was Andrea Dupree on International Ultraviolet Explorer satel- your study of rotational and radial velocities of T Tauri lite observations of all kinds of objects - globular clusters, stars. What motivated you to embark on observations? X-ray binaries, cataclysmic variables, you name it, along A: New detectors became available at Mt. Hopkins, ver- with John Raymond. My major focus eventually became sions of the intensified Reticon developed by Steve Schecht- chromospheric and coronal emission of solar-type stars, man. The Reticons were solid-state 2 x 1024 pixel arrays, which then led to my interest in T Tauri stars, which kind of forerunners of CCDs, but had huge read noise. To were supposed to be the most magnetically-active late- get around that problem, the Reticon was placed at the type stars... but that isn’t the big story. back end of a collection of image tubes (pause for young Q: In the early 1980s you wrote a series of highly influen- readers, if any, to google the term), which turned each in- tial papers with MacGregor on wave-driven winds. coming photon into a huge spray at the Reticon, defeating the read noise and allowing one to count individual pho- A: Keith had worked on rotating, magnetized solar-type tons. It was a huge improvement over what we had before, wind models for his thesis, and applied these to the very not only because of increased sensitivity but because the massive outflow in Orion-KL, showing that a magnetized data went straight into the computer without the need to protostellar cloud rotating at breakup could drive a mas- scan plates. I figured it would be useful to have a kind sive wind. But we did this for equatorial flow; at roughly of album of T Tauri line profiles using this new device. the same time the Blandford and Payne and Pudritz and In particular, I remember an Hγ profile of DF Tau where Norman papers came out on disk winds/jets driven by it showed simultaneous red- and blue-shifted absorption, magnetic fields anchored in the rotating disk. The im- and puzzling over it. Of course now we can interpret this portance of disks only became clear somewhat later with as magnetospheric infall interior to an expanding wind.

3 I think my interest in making a survey of rotation in T the infrared spectrum. As far as I know, the most compre- Tauri stars stemmed from my collaboration with John hensive comparison of a detailed SED with a steady disk Stauffer, who was leading efforts to study the subset of model for any astrophysical object is for FU Ori; as shown rapidly-rotating solar-type stars in the Pleiades. Prob- in the right panel of Figure 1 of arXiv:1106.3343, we can ably the idea was to see how initial angular momenta fit the observations over a factor of 30 in wavelength in- mapped into the Pleiades rotation allowing for contrac- cluding the absorption bands in the near- to mid-infrared. tion to the main sequence and seeing how much angular Zhaohuan Zhu, Catherine Espaillat, Ken Hinkle and I also momentum loss via winds one needed. Along with Jerome showed that the differential rotational velocities remain Bouvier’s simultaneous study, we showed the slow T Tauri consistent with Keplerian out to 4.6µm. No other model rotation more systematically than had been done before. explains all these results. (Although magnetospheric braking probably is responsi- Modeling the optical spectral lines accurately involves sev- ble for the slow rotation, exactly how it works still puz- eral subtleties, such as accounting for the non-power-law zles me.) On a personal note, it engendered about the temperature distribution of the inner disk, and in the case worst referee report I’ve ever gotten, with 70 paragraphs of FU Ori, correcting for the Doppler shifts of the emerging (I counted) of scathing criticism. I was ready to jump off disk wind. That said, the mechanism(s) of the outbursts a bridge until I received a very nice letter from George still remain unclear. Perhaps the ongoing discovery and Herbig, who liked the paper. That meant a lot to me. characterization of the weaker EXor outbursts will help. Q: In 1985 came your paper with Scott Kenyon on the na- Q: Your most cited first-author paper, together with Nuria ture of FU Orionis objects, followed by a series of studies Calvet and collaborators, is the 1998 study ′Accretion and of FUors, and culminating in your Annual Reviews article the Evolution of T Tauri Disks′. What were the key new on FUors. What were the key ideas, and how have they insights? held up with time? A: With Erik Gullbring and Cesar Briceño, we had just A: I became interested in the FUors when, as a finishing derived new accretion rates for T Tauri stars from optical- grad student at Wisconsin (the official designation was near UV excesses, using the Blue Channel spectograph on “terminal”), I went to my first AAS meeting and heard the MMT plus the luck of fabulously transparent skies to George Herbig’s wonderful Russell Lecture on “Eruptive get spectrophotometry down to about 3200 A.˚ It seemed Phenomena in Early Stellar Evolution”. This paper stuck to me that we should try to connect the mass flow with in my mind for years, so when Scott Kenyon came to CfA the disk masses that had recently begun to be estimated and gave a talk on novae, I went up to him afterward and from mm-wave dust emission. asked if FU Ori could also be some kind of young nova. Scott said he didn’t think so, but it did sound like an Now, disk accretion requires the outward transport of an- accretion disk outburst such as were then being invoked gular momentum. The similarity solution for viscous ac- to explain the recurrent eruptions of dwarf novae. cretion disks of Lynden-Bell and Pringle provided a con- venient tool to try to connect the observed accretion rates My first thought was to look for the double-peaked ab- with limits on disk masses and radii in order to get a sorption line profiles one would expect for a disk, but was handle on the rate of angular momentum transport - as ˚ having little success taking spectra at 5200 A. Then Peter parameterized by the “alpha” viscosity. For a given ac- Petrov visited CfA and told me about some HIRES red cretion rate, higher viscosities mean more rapid disk ex- spectra that he and Herbig had taken which showed dou- pansion and lower disk masses. Unfortunately it is un- ble absorption lines in FU Ori as if it were a double-lined likely that protoplanetary disks are fully viscous - indeed, spectroscopic binary, but the lines didn’t vary in radial there are current simulations which suggest that there isn’t velocity. I became very excited, and even had the nerve enough ionization for even active layer accretion, and that to cold-call George in Hawaii to tell him he had discovered at least at intermediate disk radii the accretion is driven the signature of an accretion disk. George was noncom- by a disk wind. So I think at the current time the value of mittal; as you know, he never liked the disk model, and these models is as sort of a benchmark to compare against wrote papers with Peter trying to support alternative ex- the behavior of more complicated disk simulations, and to planations. Anyway, we eventually got red spectra with remind people that T Tauri disks must be continuously the MMT echelle which showed the line doubling. We evolving, not simply in terms of forming planets etc. but subsequently went to the Kitt Peak 4m FTS and obtained also by virtue of accretion onto the central star. high-resolution 2 µm spectra which showed slower infrared rotation, as expected for a Keplerian disk. Q: Spitzer photometry has been remarkably efficient in characterizing the circumstellar disks of T Tauri stars. I think the accretion disk picture has held up extremely You have been involved in a number of disk studies using well. The criticisms of it have basically come from looking IRAC, IRS, and MIPS. at the optical spectral lines in isolation without addressing

4 A: We were fortunate to have been able to collaborate face densities were large enough that self-gravity would be with the IRAC and IRS GTO teams led by John Stauffer, important and so star formation could ensue rapidly, in Lori Allen, Tom Megeath, Dan Watson, and Bill Forrest. I agreement with observations. was trying to improve the statistics on disk lifetimes using The Spitzer surveys of more distant star-forming regions the IRAC surveys of young clusters in collaboration with have made it increasingly clear that star-forming clouds the above people, much of it done by Jesus Hernandez. get blown apart quickly by massive star energy input, so We also used the expanding shells of Cep OB2 to provide slow formation can’t work. Because one can collect gas independent age-dating at 3 Myr and 10 Myr for Tr 37 and along field lines, you can solve the “magnetic flux problem” NGC 7160, respectively, in Aurora Sicilia-Aguilar’s thesis by simply increasing the mass rather than decreasing the work. While we have a much better statistical picture of magnetic flux. the evolution of disk infrared excesses thanks to IRAC, the real advance was in the IRS studies of the pre/transitional I think a lot of the pushback against rapid cloud and star disks lead by Nuria, Paola D’Alessio, and Catherine Es- formation and short cloud lifetimes arose because of se- paillat showing that T Tauri disks are much more struc- mantics. For example, extragalactic observers and theo- tured, with gaps and holes, than we realized. rists tend to work on scales > 100 pc, so that, for instance, the Orion Ia and Ib-d associations are all one region with Q: In 1998 came your widely read book ′Accretion Pro- ′ star formation going on over ≥ 10 Myr, whereas we galac- cesses in Star Formation , which appeared in a second edi- tic astronomers distinguish between the 10 Myr-old Ia as- tion in 2008. What motivated you to write this book? sociation without gas and active star formation from the A: Doug Lin suggested writing the book on behalf of Cam- younger molecular cloud regions. Another argument is bridge University Press. I accepted the challenge because I that star formation in galaxies mainly occurs where most figured it would be a good opportunity to learn about a lot of the gas is molecular, so you have to make molecular of things I didn’t know. A decade later I thought so much clouds out of molecular gas. Setting aside the question of more had been learned that a second edition was needed, what is a molecular cloud when all the gas is molecular, but I’m not entirely satisfied with it. I’m currently work- this obviously has little to do with our analysis of condi- ing on a shorter, biased version that allows me to mount tions (explicitly) in the solar neigborhood, where most of a few hobbyhorses; I’ll put this on the web someday. the gas is atomic (or, to be pedantic, not strongly emitting Q: In the last decade you have developed theoretical ideas in CO, whatever you think the H2 fraction is). on rapid formation of molecular clouds and rapid star for- Q: You and Nuria moved from the Harvard-Smithsonian mation, which have led to much debate. What are the key Center for Astrophysics to the University of Michigan to issues, and how do these ideas hold up against observa- join the star formation group there. How is that going? tions? A: I think we - with Ted Bergin and John Monnier - have A: The standard picture from the 80s predicted that star been pretty productive in star formation and protoplan- formation was slow because the collapse of protostellar etary disk structure and evolution over the past several cores is regulated by magnetic flux loss via ambipolar dif- years. We’ve been lucky to have had several excellent fusion. But Herbig, Vrba, and Rydgren looked for the grad students - for my part, Zhaohuan Zhu and John To- older, “post-T Tauri” stars in Taurus, and didn’t find any. bin have done terrific work on disks and protostars. Even We also searched in Taurus using a proper motion survey though Tina Hsu left the field, I’m still proud of the work with John Stauffer and Burt Jones and a wide-field objec- she did on showing that the upper mass IMF in L1641 is tive prism survey by Cesar Briceño, and also didn’t find different from that of the Orion Nebula region. significant numbers of PTTS, with an age spread compa- Q: What problems are you currently focused on? rable to or larger than the crossing time. A: I’m interested in how star clusters form, working with Then when Javier Ballesteros visited CfA in the late 90s a student, Marina Kounkel, as part of Laurent Loinard’s he showed me some old large-scale ISM simulations by VLBA program to add proper motions to radial veloci- Enrique Vazquez and collaborators with stellar energy in- ties, and develop a full picture of cluster kinematics, in put driving large-scale flows. It quickly became clear to particular those of the Orion Nebula. Concerning disks, me that one could eliminate the crossing time problem by I’m working with another student, Jaehan Bae, on making having flows pile up clouds that were elongated perpen- more realistic models of outbursting disks; we’ve also been dicular to the flow direction; there was no need to propa- making some initial attempts to understand the frequency gate information in the long direction. With Javier, Ted distribution of disk lifetimes in terms of photoevaporation Bergin, and later Fabian Heitsch, we showed that initially working on a population of disks with differing initial an- atomic gas, when swept up, would not be visible in CO gular momenta. I wish I had a better understanding of until there was sufficient shielding; and by that time, sur- why T Tauri disks accrete...

5 My Favorite Object 133P/(7968) Elst-Pizarro Henry Hsieh

Figure 1: Composite R-band image of 133P constructed from observations on 2002 September 7 using the Univer- sity of Hawaii 2.2 m telescope on Mauna Kea. The nucleus of the comet is at the upper left corner with the ∼ 3.5′- long dust trail extending down and to the right. Field stars and galaxies appear as dotted trails due to the shifting and alignment of individual exposures prior to construction of the composite image to follow the apparent non-sidereal The Discovery of 133P motion of the comet relative to background stars.

Some discoveries in astronomy represent the culmination of years or even decades of work towards a specific goal. Other discoveries are serendipitous but are nonetheless the case of an impact, one would expect to see dust (i.e., recognized as significant at the time at which they are impact ejecta) ejected only at the moment of impact. On made. The case of comet 133P/Elst-Pizarro, also known the other hand, prolonged dust emission is a natural con- as asteroid (7968) Elst-Pizarro, is a story of a serendipi- sequence of sublimation. As long as an object remains at tous discovery whose significance was somehow not quite a temperature high enough for sublimation to occur and fully recognized until years later. Over time, however, this ice is still present, one can expect ongoing dust emission. strange object has proven to be extraordinarily fascinat- Sublimation-driven dust emission is a hallmark of comets, ing, and has ultimately led to the opening of an entirely which are typically assumed to originate in the cold outer new field of solar system research representing new oppor- solar system where their volatile contents can remain pre- tunities for probing the primordial and present-day distri- served. As such, the apparent discovery of such an ob- bution of water in the inner solar system. ject in the much warmer main asteroid belt was puzzling 133P/Elst-Pizarro (hereafter, 133P) was discovered in 1979 enough that controversy remained for many years after as an inactive outer main-belt asteroid. On 1996 Au- 133P’s discovery as to whether the activity was in fact gust 7, it was discovered to be cometary by Eric Elst and sublimation-driven (e.g., Boehnhardt et al., 1998), or the Guido Pizarro (Elst et al., 1996) using the 1.0 m Euro- consequence of an impact (e.g., Lien, 1998; Tóth, 2000). pean Southern Observatory Schmidt telescope at La Silla. As it was first identified as an inactive asteroid, it became The Return of Activity one of only a few objects to receive both asteroidal and cometary designations. Other examples of objects with Observations in 2002 by me and David Jewitt showed that dual designations at the time included the active Centaur 133P had become active once again (Figure 1), and as be- 95P/(2060) Chiron, and near-Earth object 107P/(4015) fore, numerical modeling indicated that the dust trail was Wilson-Harrington, but 133P was the only comet known the result of a prolonged dust emission event (Hsieh et al., at the time to actually orbit in the main asteroid belt. 2004). This rediscovery of activity largely eliminated the Numerical modeling of 133P’s 1996 dust trail indicated possibility that 133P’s active behavior could be the result that the dust was emitted over a prolonged period of time of impacts. In principle, a complex (and contrived) event (i.e., several weeks or months; Boehnhardt et al., 1996), consisting of multiple impacts in rapid succession (e.g., a finding inconsistent with an impact event and strongly Tóth, 2000) could have accounted for 133P’s prolonged suggestive of cometary, or sublimation-driven, activity. In dust emission event in 1996. However, the likelihood of

6 such an event occurring twice within the span of six years day activity would be easily explained as a result of it be- and at a similar portion of the object’s orbit (shortly fol- ing a recent visitor to the inner solar system from the outer lowing perihelion), when we do not see similar events oc- solar system, but its orbit is puzzling. The Tisserand pa- curring at anywhere near the same frequency or regularity rameter, TJ , is a commonly used dynamical discriminant on other asteroids, was judged to be exceedingly low. between asteroids and comets, roughly indicating the de- In Hsieh et al. (2004), we presented a detailed physical gree of dynamical coupling between an object and Jupiter. study of 133P, where we found the nucleus to have an ef- It is computed from the semimajor axis (a), eccentricity (e), and inclination (i) of an object using fective diameter of de =5.0±0.2 km, an axis ratio of a/b = 1.45 ± 0.07, a rotation period of P = 3.471 ± 0.001 hr, 1 2 rot a a / a minimum density of ρ = 1300 kg m−3, and broadband T = J +2cos i 1 − e2 (1) J a a optical colors typical of C-type (primitive, carbonaceous) J asteroids. Numerical dust modeling found that the tail where aJ is the semimajor axis of Jupiter. Asteroids typ- consisted of dust particles ∼1-20 µm in radii released from ically have TJ > 3 and comets typically have TJ < 3, 133P’s nucleus at velocities of ∼1-2m s−1 over a minimum where 133P’s Tisserand parameter value is TJ = 3.18, period of 5 months (between 2002 July to 2002 November). indicating that it is completely decoupled from Jupiter, We considered multiple alternate mechanisms for explain- unlike most other JFCs which are normally captured onto ing 133P’s activity, but none fit all the available evidence. short-period orbits by Jupiter and then stay dynamically The possibility that the 1996 emission event had left be- coupled afterwards. If 133P was originally a JFC, decou- hind residual dust in the form of a so-called “neck-line pling could have occurred through a combination of per- structure” (Pansecchi et al., 1987) was ruled out because turbations from close encounters with the terrestrial plan- the relative geometry of the 1996 and 2002 observations ets and from non-gravitational forces such as asymmet- was inconsistent with the 2002 dust trail being a neck-line rical cometary outgassing. 133P’s current activity levels structure. Electrostatic dust levitation, like that observed are extremely weak relative to other comets, however, and on the Moon (e.g., De & Criswell, 1977), was ruled un- unlikely to significantly change the orbit of an object of likely because there was no clear mechanism for replen- its size, although it should be noted that its activity may ishing mobile surface dust lost by such a process, and be- have been much stronger in the past. cause rapid rotation like that observed for 133P actually Ipatov & Hahn (1997) found 133P’s orbit to be stable over diminishes the effectiveness of such a mechanism since less at least 200 Myr under purely gravitational forces, while photoelectric charge can be accumulated before a given simulations by Fernández et al. (2002) were unable to re- point of the surface rotates back into darkness. There was produce 133P-like orbits from JFC-like orbits under purely also no plausible explanation as to why 133P would show gravitational forces. These results indicate that if a JFC such behavior while other asteroids did not, or how 133P can evolve onto a 133P-like orbit, it probably only occurs would show such behavior only over a certain portion of its rarely. Non-gravitational forces could change the results orbit. Finally, the possibility that 133P could eject dust of these simulations, though even then, they would likely through rotational instability induced by its rapid rotation need to act very precisely in order to reproduce 133P’s or- was considered, but ruled out due to the lack of a plau- bit from a JFC-type orbit. Practically speaking, the diffi- sible explanation for the intermittent but periodic nature culty of evolving a JFC onto a 133P-like orbit means that of the observed activity, as well as the lack of observations if 133P was truly an evolved JFC, it might be extremely of similar behavior on other rapidly rotating asteroids. rare, and possibly the only object of its kind. On the other hand, it is at least physically plausible that Evolved Comet or Icy Asteroid? 133P could simply be an icy asteroid. Spectral features attributed to hydrated minerals (indicative of at least the Based on all the evidence considered in Hsieh et al. (2004), past presence of liquid water) have been observed for main- 133P appeared to be an object exhibiting mass loss due belt asteroids in the infrared at 3 µm (e.g., Lebofsky, 1980; to the sublimation of volatile ices, i.e., a comet. This Lebofsky et al., 1981; Feierberg et al., 1985; Jones et al., conclusion then led us to ask whether (1) 133P was a 1990) and in the visible at 0.7 µm (e.g., Vilas et al., 1994, short-period Jupiter-family comet (JFC) from the outer Barucci et al., 1998). Hydrated minerals have also been solar system that had somehow dynamically evolved onto found in aqueously altered CI and CM carbonaceous chon- an asteroid-like orbit, or (2) 133P was an otherwise ordi- drite meteorites, which have been determined to have orig- nary main-belt asteroid, formed in situ, that had somehow inated from C-type asteroids in the main belt (e.g., Hiroi managed to preserve enough icy material over the age of et al., 1996; Burbine, 1998; Keil, 2000). the solar system to exhibit present-day cometary activity. Hydrated minerals of course only indicate that water was If 133P was an evolved JFC, its volatile content and present- present in the past, but thermal modeling by Grimm &

7 McSween (1989) of CM chondrite production predicts that Veritas clusters (which are extremely young families which for small bodies, the bulk of each body’s ice must remain may be promising places to search for objects with fresh frozen in order to produce the temperature distribution near-surface ice; Nesvornýet al., 2002; Nesvornýet al., dictated by aqueous alteration models. They addition- 2003); and the low-inclination asteroid population in gen- ally suggested that ice in large asteroids, like Ceres, at 3 eral since collision rates have been found to be enhanced AU could be stable against sublimation from solar heat- for asteroids with low inclinations (Farinella & Davis, 1992). ing at depths of just tens of meters, a result corrobo- rated by modeling by Fanale & Salvail (1989). If sub- surface water ice could be preserved on 133P over Gyr timescales, a recent impact event that excavated some of that ice could be the trigger needed to induce the onset of present-day cometary activity. We note that this impact-excavation hypothesis differs from the impact-only scenarios that were initially used to try to explain 133P’s behavior in that, under this scenario, the impact only provides the trigger for activity, which is then sustained by sublimation of the exposed ice. As we argued in Hsieh et al. (2004), however, if 133P is an ordinary main-belt asteroid that happens to contain preserved ice, and is not particularly unique in any way (e.g., does not contain an unusually large amount of ice, or experiences an unusually high rate of impacts able to trigger activity), other main-belt asteroids should also exhibit cometary outgassing. The absence of other known Figure 2: Semimajor axis vs. eccentricity plot of objects active main-belt asteroids at the time was an argument surveyed as part of the Hawaii Trails Project survey which against this “icy asteroid” hypothesis, but also presented aimed to find other 133P-like cometary objects in the main a straightforward way to test the hypothesis: a sufficiently asteroid belt. Different categories of survey targets are in- deep survey of a sufficient number of main-belt asteroids dicated with different colors and symbols as labeled. The should reveal other 133P-like objects. locations of 133P as well as other main-belt comets known at the time of publication, including 176P/LINEAR which was discovered as part of the survey, are marked with Discovery of the Main-Belt Comets white X symbols. The background asteroid population is indicated with small black dots. From Hsieh (2009). The implication of a population of undiscovered cometary main-belt asteroids from our work on 133P led us to embark on a search for these objects. In our survey, dubbed In total, observations of 599 unique asteroids were made the Hawaii Trails Project (Hsieh, 2009), we sought to ob- using a range of facilities including 1.0 m telescopes at serve asteroids as similar to 133P as possible. 133P is Lulin and Cerro Tololo up to the 8-10 m Subaru, Gem- dynamically associated with the Themis collisional fam- ini North, and Keck I telescopes. One of these objects, ily, which consists of thousands of asteroids with similar Themis family asteroid (118401) 1999 RE70, was found to orbital elements and was created by the catastrophic dis- be cometary by Gemini North as part of the survey in ruption of a large parent body, perhaps hundreds of km November 2005, (Hsieh et al., 2006) and re-designated as in size about 2 Gyr ago (Marzari et al., 1995). Because of 176P/LINEAR, while by pure coincidence, a third main their common origin, Themis family members should have belt object, P/2005 U1 (Read) (now 238P/Read), was similar compositions (cf. Florczak et al., 1999; Ivezićet al., serendipitously discovered to be cometary just a month 2002), and so if 133P is a true member of the Themis fam- before in October 2005 (Read et al., 2005). ily, other members could also be icy and might also exhibit The discovery of two more cometary main-belt objects was sublimation-driven dust emission. Due to the clustering of strong circumstantial evidence that all three objects, in- objects in orbital element space and their low inclinations, cluding 133P, were in fact native to the asteroid belt. The Themis asteroids also experience higher than typical colli- previously discussed dynamical results where no dynami- sion rates (Farinella & Davis, 1992; Dell’Oro et al., 2001). cal pathway could be found between a JFC-like orbit and We also selected targets from the Koronis family (which a main-belt orbit implied that if 133P was a JFC that had is characterized by even higher collision rates than the nonetheless managed to successfully undergo that dynam- Themis family; Farinella & Davis, 1992), the Karin and ical transition through a fortuitous combination of ter-

8 restrial planet encounters and non-gravitational forces, it should be extremely rare. On the other hand, if 133P was an ordinary native main-belt asteroid, we would expect to ﬁnd many more. The limited data (i.e., observations of just ∼600 asteroids) that we required to discover 176P and the serendipitous discovery of 238P indicated that 133P was not in fact rare, and implied that there could be a population on the order of ∼100 such objects in the asteroid belt. A new class of objects had been discovered, objects that we dubbed “main-belt comets” (MBCs; Hsieh & Jewitt, 2006), and a new research ﬁeld was born. Figure 3: Images of the known MBCs (top two rows) and disrupted asteroids (bottom row). Recent Research

Interest in MBCs is partly related to the simple fact that they are a relatively new and unexpected class of solar system objects, but also for the potential that they provide for better understanding the volatile content of inner solar system bodies (located, and probably formed, interior to the orbit of Jupiter), constraining temperature and composition in the protosolar disk, and probing a possible primordial source of water on Earth. As such, research on these mysterious observationally cometary (Figure 3) yet dynamically asteroidal (Figure 4) objects has advanced considerably since their discovery. Figure 4: Semimajor axis vs. eccentricity plot for num- Several more MBCs have been discovered and all have bered asteroids (small black dots), classical comets (blue undergone detailed physical analyses (e.g., Hsieh et al., dots), MBCs (green circles), and disrupted asteroids (red 2009a, 2011, 2012a,b, 2013; Jewitt et al., 2009, 2014a; circles). The semimajor axes of Mars and Jupiter (aMars Licandro et al., 2011, 2013; Moreno et al., 2011, 2013). and aJup) and major mean-motion resonances with Jupiter Thermal models have been developed (e.g., Schörghofer, are marked with vertical dotted lines. Objects to the left 2008; Prialnik & Rosenberg, 2009; Capria et al., 2012), of the curved dotted line marked as “Q = qJup” never dynamical analyses have been performed (e.g., Haghigh- cross the orbit of Jupiter. MBCs and disrupted aster- ipour, 2009; Novakovićet al., 2012), and surveys have been oids are seen to be clearly dynamically distinct from other conducted to search for more MBCs and estimate the pop- comets, and dynamically indistinguishable from main-belt ulation size (e.g., Gilbert & Wiegert, 2009; Sonnett et al., asteroids. After Hsieh & Jewitt (2006). 2011; Waszczak et al., 2013; Cikota et al., 2014). Since all of the evidence described above that dust emission in MBCs is sublimation-driven is still indirect, attempts have ing been observed to be active on four separate occasions been made to directly detect outgassing (e.g., Jewitt et al., now, in 1996, 2002, 2007, and 2013, with physical studies 2009, 2014a; Licandro et al., 2011; Hsieh et al., 2012a,b, performed during inactive phases as well (e.g., Hsieh et al., 2013; de Val-Borro et al., 2012; O’Rourke et al., 2013), 2009b, 2010; Bagnulo et al., 2010; Licandro et al., 2011; though all have been unsuccessful to date, likely due to Rousselot et al., 2011; Jewitt et al., 2014b). The wealth of the extremely low levels of activity exhibited by all of the knowledge that we have about 133P means that it is ex- known MBCs. Independent direct indicators of present- tremely useful as a prototype for understanding the MBC day water ice or water vapor in the main belt have been population as a whole, and as such, has even been pro- discovered, however (e.g., Rivkin & Emery, 2010; Campins posed as the target of a potential space mission to study et al., 2010; Küppers et al., 2014). As one can see, there MBCs (Hilchenbach, 2013; http://bit.ly/mbcmission). has been far too much work done to describe everything in this short article, but reviews by Bertini (2011) and Jewitt In terms of general MBC research, one key development (2012) cover many of the major findings. has been the discovery of disrupted asteroids. Earlier when discussing the discovery of 133P, I mentioned the Meanwhile, 133P has continued to attract interest since fact that some astronomers believed that 133P’s dust emis- its reactivation in 2002 and the discovery of other MBCs. sion could be the result of an impact. In the case of 133P, As the first known MBC, it is also the best studied, hav- we ruled out this possibility based on several lines of ev-

9 idence including dust modeling results and the activity’s recurrence. In recent years, though, main-belt asteroids exhibiting comet-like activity that is likely to be the result of impacts or other disruptions such as rotational disrup- tion, have actually been discovered. This discovery has led to the classification of both main-belt comets (where activity is strongly believed to be the result of sublimation- driven dust emission) and disrupted asteroids (where activity is likely not sublimation-driven) under the umbrella term “active asteroids” (cf. Jewitt, 2012). Another interesting development has been the revelation that some MBCs are not only members of the ∼2-Gyr-old Themis family (which claims three MBCs — 133P, 176P, Figure 5: Plots showing the distribution of D/H ratios and 288P — as members, with 238P as a possible for- for various solar system bodies (left) and in carbonaceous mer member; Haghighipour, 2009), but are also members meteorites compared to Earth ocean water and comets of much younger sub-families. Both 133P and 288P have (right). From Robert (2001). been found to belong to subfamilies within the Themis family that are < 10 Myr old (Nesvornýet al., 2008; No- vakovićet al., 2012). If these objects are indeed recently number of comets (mostly long-period comets from the produced fragments from the interiors (where ice can re- Oort Cloud) and so it is also unclear whether those values main much better insulated against solar heating) of much are representative of all comets, particularly JFCs. In fact, larger icy parent bodies, it could provide a plausible phys- the D/H ratio recently measured for JFC 103P/Hartley 2 ical explanation for how they have managed to retain so does appear to be ocean-like (Hartogh et al., 2011; Figure much near-surface volatile material today. Not all MBCs 6), meaning that completely ruling out classical comets as have been associated with young families at the present a source of terrestrial water may be premature. time, of course, but as more asteroids continue to be discovered by large-scale surveys, this may change in the future (cf. Milani et al., 2014).

Astrobiological Implications

As mentioned above, one of the main aspects of interest in 133P and other MBCs is the potential they offer for probing conditions in the early solar system, and specifi- cally for exploring the hypothesis that much of the Earth’s present-day water was delivered by impacting icy asteroids from what is now the main asteroid belt (e.g., Morbidelli Figure 6: Plot showing the distribution of D/H ratios mea- et al., 2000; Raymond et al., 2004; Albarede et al., 2013). sured for Earth ocean water (dark blue line), CI carbona- Comets certainly contain much more ice than asteroids, ceous chondrites (green square), Oort cloud comets (or- and would therefore seem to be the best candidates for ange squares), 103P/Hartley 2 (purple square), H2 in the delivering water to the dry, early Earth. However, iso- giant planets (black squares), and water in the plumes of topic measurements of the deuterium-to-hydrogen (D/H) the Saturnian moon Enceladus (blue square). From Har- ratio in carbonaceous chondrites, and therefore of C-type togh et al. (2011). main-belt asteroids, have been found to match the D/H ratio in terrestrial ocean water much more closely than that of the handful of comets for which D/H has been The close match between the D/H ratios in ocean water measured (e.g., Robert, 2001; Figure 5). and carbonaceous meteorites (e.g., Figure 5) does appear There are some caveats, however. First, it is unclear compelling, though. However, just as the D/H ratio in whether D/H measurements of cometary comae are actu- cometary comae could be different from that of the bulk ally representative of the bulk ice in the comets that were ice in the comets themselves, it is also unclear how repre- actually measured (since some fractionation could occur sentative the D/H ratio measured for hydrated minerals as part of the sublimation process; Weirich et al., 2004). (i.e., bound water) in carbonaceous chondrites is of bulk D/H ratios have also only been measured for a very small ice (i.e., unbound water) in the parent asteroids where the

10 aqueous alteration of those minerals first took place. The Hartogh, P., et al. 2011, Nature 478, 218 discovery of the MBCs means, however, that appreciable Hilchenbach, M. 2013, AGU Fall Meeting Abstracts, A1754 amounts of bulk water ice, presumably preserved since the Hiroi, T., et al. 1996, Meteoritics & Planetary Science 31, 321 Hsieh, H. H. 2009, A&A 505, 1297 birth of the solar system, is still present in the main belt Hsieh, H. H., Jewitt, D., Fernández, Y. R. 2004, AJ 127, 2997 and could be studied (i.e., have its D/H ratio measured). Hsieh, H. H., Jewitt, D. 2006, Science 312, 561 Hsieh, H. H., et al. 2006, IAU Circ. 8704, 2 Given that we have been unable to detect outgassing from Hsieh, H. H., et al. 2009a, AJ 137, 157 a MBC at all using existing ground- or space-based facili- Hsieh, H. H., et al. 2009b, ApJ Letters, 694, L111 ties, however, let alone measure the isotopic ratios within Hsieh, H. H., et al. 2010, MNRAS 403, 363 Hsieh, H. H., et al. 2011, AJ 142, 29 the outgassing, what may ultimately be needed is a space- Hsieh, H. H., et al. 2012a, ApJ Letters 748, L15 craft rendezvous with one of these objects to study its Hsieh, H. H., et al. 2012b, AJ 143, 104 chemical and isotopic composition in detail. By doing so, Hsieh, H. H., et al. 2013, ApJ Letters 771, L1 we would not just help to answer the question of whether Ipatov, S. I., Hahn, G. J. 1997, LPSC Abstracts 28, 619 Ivezić, Z, et al. 2002, AJ 124, 2943 the ancient cousins of today’s MBCs could have provided Jewitt, D., et al. 2009, AJ 137, 4313 a significant amount of the Earth’s present-day water, Jewitt, D. 2012, AJ 143, 66 but also set valuable constraints on the compositional and Jewitt, D., et al. 2014a, ApJ Letters 784, L8 temperature structure of the protosolar disk itself. Jewitt, D., et al. 2014b, AJ 147, 117 Jones, T. D., et al. 1990, Icarus 88, 172 Keil, K. 2000, Planet. & Space Sci. 48, 887 Küppers, M., et al. 2014, Nature 505, 525 Conclusions Lebofsky, L. A. 1980, AJ 85, 573 Lebofsky, L. A., et al. 1981, Icarus 48, 453 In closing, I would just note how far we have come in less Licandro, J., et al. 2011, A&A 532, A65 than 20 years since the discovery of 133P when it was Licandro, J., et al. 2013, A&A 550, A17 Lien, D. J. 1998, BAAS 30, 1035 little more than a fleeting curiosity in the asteroid belt, Marzari, F., Davis, D., Vanzani, V. 1995, Icarus 113, 168 compared to how rich the field of MBC research is to- Milani, A., et al. 2014, Icarus 239, 46 day. Excitingly, we likely have even more to look forward Morbidelli, A., et al. 2000, Meteoritics & Planetary Science 35, 1309 to, with current and future surveys continuing to discover Moreno, F., et al. 2011, ApJ Letters 738, L16 Moreno, F., et al. 2013, ApJ Letters 770, L30 more MBCs, giving hope to us eventually reaching a point Nesvorný, D., et al. 2008, ApJ Letters 679, 143 where the known population is large enough that we can Novaković, B., Hsieh, H. H., Cellino, A. 2012, MNRAS 424, 1432 actually use it to trace the water content of the present- O’Rourke, L., et al. 2013, ApJ Letters 774, L13 Pansecchi, L., Fulle, M., Sedmak, G. 1987, A&A 176, 358 day asteroid belt, and then use thermal and dynamical Prialnik, D., Rosenberg, E. D. 2009, MNRAS Letters 399, L79 models to try to tease out the primordial abundance and Raymond, S. N., Quinn, T., Lunine, J. I. 2004, Icarus 168, 1 distribution of volatile material in the main-belt region of Read, M. T., et al. 2005, IAU Circ. 8624, 1 our solar system. That would be quite the legacy for 133P, Rivkin, A. S., Emery, J. P. 2010, Nature 464, 1322 Robert, F. 2001, Science 293, 1056 and I for one am certainly looking forward to seeing what Rousselot, P., Dumas, C., Merlin, F. 2011, Icarus 211, 553 the next 20 years brings! Schörghofer, N. 2008, ApJ 682, 697 Sonnett, S., et al. 2011, Icarus 215, 534 References: Tóth, I. 2000, A&A 360, 375 Vilas, F., et al. 1994, Icarus 109, 274 Albarede, F., et al. 2013, Icarus 222, 44 Waszczak, A., et al. 2013, MNRAS 433, 3115 Bagnulo, S., et al. 2010, A&A 514, A99 Weirich, J. R. 2004, BAAS 36, 1143 Barucci, M. A., et al. 1998, Icarus 132, 388 Bertini, I. 2011, Planet. Space Sci. 59, 365 Boehnhardt, H., et al. 1996, IAUC 6495, 1 Boehnhardt, H., et al. 1998, Highlights in Astronomy 11, 233 Burbine, T. H. 1998, Meteoritics & Planetary Science 33, 253 Campins, H., et al. 2010, Nature 464, 1320 Capria, M. T., et al. 2012, A&A 537, A71 Cikota, S., et al. 2014, A&A 562, A94 De, B. R., Criswell, D. R. 1977, J. Geophys. Res. 82, 999 de Val-Borro, et al. 2012, A&A 546, L4 Dell’Oro, A., et al. 2001, Icarus 153, 52 Elst, E. W., et al. 1996, IAUC 6456, 1 Farinella, P., & Davis, D. R. 1992, Icarus 97, 111 Feierberg, M. A., Lebofsky, L. A., Tholen, D. J. 1985, Icarus 63, 183 Fanale, F. P., Salvail, J. R. 1989, Icarus 82, 97 Fernández, J. A., Gallardo, T., Brunini, A. 2002, Icarus 159, 358 Florczak, M., et al. 1999, A&AS 134, 463 Gilbert, A. M., Wiegert, P. A. 2009, Icarus 201, 714 Grimm, R. E., McSween, H. Y., Jr. 1989, Icarus 82, 244 Haghighipour, N. 2009, Meteoritics & Planetary Science 44, 1863

11 Circumstellar planets in binary star systems A survey of the currently known planet-hosting stars indicates Perspective that slightly more than 10% of these objects are members of binary or multiple star systems1. If the planetary sys- Planet formation in and tems detected by the Kepler telescope are excluded (as we around binary stars lack knowledge of their stellar multiplicity), this fraction will increase to approximately 25% (Haghighipour 2006). Nader Haghighipour With the exception of the recent discovery of a planet around the primary of the binary OGLE-2013-BLG-0341, all these planets have been detected using the radial velocity technique. The host binaries in almost all these systems are wide with separation between 250 AU and 6000 AU. At such large separations, the perturbing effect of the farther stellar companion on the formation and dynamical evolution of planets around a star of a binary is negligible. There are, however, 7 systems that do not fall into this cat- egory. The binary separation in these systems, namely GL 86 (Queloz et al. 2000, Eggenberger et al 2003), γ Cephei (Hatzes et al 2003, Endl et al 2011), HD 41004 (Zucker et al 2004), HD 196885 (Correia et al 2008, Chauvin et al 2011), HD 176051 (Muterspaugh et al 2010), α Centauri Among most, the phrase a planetary system triggers the (Dumusque et al 2012, Hatzes 2013), and the microlensing thought of a single star orbited by several planets, very system OGLE-2013-BLG-0341 (Gould et al 2014) ranges much like our solar system. This is a natural reaction between 15 AU and 24 AU suggesting that their secondary as the concept of a planetary system was indeed devel- stars must have played an important role in the formation oped based on our solar system and was presented and and final orbital architecture of their planets. used primarily in that context. The connection between The detection of planets around a star of a binary in such a planetary system and single stars is so deeply rooted in close binary systems opened a new chapter in exoplane- our minds that we do not naturally think of binary stars tary science. The fact that these planets exist came as a as a planet-hosting environment. This is despite the fact big surprise as almost a decade before the confirmation of that more than 50% of main and pre-main sequence stars the first of such planetary systems, computational simu- are in fact in binaries or multiple star systems. This un- lations of the evolution of disks around stars of a binary realistic contrast between binaries and planetary systems had shown that in close binary systems, the interaction used to be so strong that some old astronomy textbooks between one star and the circumstellar disk around the suggested that depending on the rate of the rotation of other can render the disk devoid of planet-forming mate- the molecular cloud, the final product of its collapse could rial. These interactions dynamically excite solid objects be either a single-star planetary system, or a binary star, by increasing their orbital eccentricities, causing them to but not both. be scattered out of the system (disk truncation, Fig. 1) The discovery of extrasolar planets during the past two (Artymowicz & Lubow 1994, Müller & Kley 2012) or pro- decades, however, changed this view (see Haghighipour hibit their growth by increasing their relative velocities 2010 for a review). Radial velocity observations, and re- which in turn causes their collisions to result in breakage cently the microlensing technique have been able to find and fragmentation (Thebault & Haghighipour 2014). In many circumstellar planets in binary star systems, and other words, it would be unlikely that planet formation in the data from the Kepler space telescope has enabled us these highly perturbed environments could proceed unaf- to detect several circumbinary planets. fected by the presence of the companion star. The detection of the planet of γ Cephei in 2003 by Hatzes et al was With the realization of planets around a star of a binary a breakthrough in the sense that it showed planet forma- or in circumbinary orbits, several fundamental questions tion around a star of a binary is robust, and can efficiently have now been raised. For instance, how did these planets occur in close binary systems as well. form? How did they acquire their current orbital configuration? And finally, does the existence of planets in and Planet formation around a star of a binary It is around dual-star systems carry any indication of the pos- generally assumed that planet formation around a star of a sibility of the habitability of these objects (Haghighipour 1See http://www.univie.ac.at/adg/schwarz/multiple.html for a & Kaltenegger 2013, Kaltenegger & Haghighipour 2013). complete and up to date list of planet-hosting binary star systems.

12 binary proceeds in the same fashion as around single stars. The argument is usually made by referring to the binary system L1551 (Fig. 2, Bieging & Cohen 1985, Rodriguez et al 1998). With a stellar separation of 45 AU, each star of this binary carries a disk, 10 AU in radius and massive enough (0.05 solar-masses) to form planets. The possibility of planet formation in binary stars has also been studied numerically for a few binaries where simulations have indicated that the primordial disks around the stars of those binaries could have maintained enough material for planet formation to proceed successfully (Jang-Condell 2008). Despite all this observational and computational support, planet formation around a star of a binary suffers from several major drawbacks. As shown by Zsom et al (2011), in close binaries, the growth of dust particles to larger objects is hindered as the perturbation of the secondary stars, especially during its periastron passage, increases the relative velocities of mm-sized particle and larger objects causing their collisions to result in breakage and fragmentation. These effects are stronger in an eccentric binary as the companion star increases the eccentricity of the gaseous disk around the primary and causes the velocity of the gas to deviate from the range that would accommodate the accretion of solid objects (Paardekooper et al Figure 1: Disk truncation around the primary of a binary 2008). star system. The masses of the stars and the binary sepa- Even if dust particles succeeded to grow to km-sized plan- ration are equal to those of the γ Cephei system. The top etesimals, the resulting planetesimal disk would still en- panel shows the disk at the beginning of the simulation. counter difficulties in forming larger objects. The perturb- The bottom panel represents the state of the disk after ing effect of the secondary star excites the orbits of plan- over 200 binary periods. etesimals and increases their orbital eccentricities. The latter causes the relative velocities of planetesimals to increase which causes their collision to result in shattering lar to γ Cephei, only for unrealistically low disk viscosities, and fragmentation (Thebault et al 2004). Computational the disk lifetime becomes long enough to allow for in-situ simulations have indicated that even if this process occurs giant planet formation by the core-accretion model. Ob- while the gas is still present (to damp the eccentricities of servational confirmation of such short-lived disks has been solid objects, Marzari & Scholl 2000), the growth of plan- obtained by Kraus et al (2012), who compared the disk fre- etesimals through mutual collisions will remain inefficient. quency as a function of age for close (≤ 40AU) binaries in These simulations have also shown that gas drag creates a several nearby young associations. They found that the size-sorting effect, meaning that objects of the same size majority of such systems lose their disks in less than 1 will have higher potential to collide and accrete whereas Myr, even though a small fraction of them are still able to objects with different sizes will shatter one another (The- retain their disks for ages close to 10 Myr. bault et al 2004, 2006). It has been suggested that the efficiency of planetesimal A more important issue regarding planet formation in bi- accretion can increase if the disk is inclined with respect to naries is the migration of solid objects. The viscous evolu- the orbital plane of the binary (Xie & Zhou 2009, Xie et al tion of a compact disk is much faster than that of the disk 2010). However, despite this inclination effect, the inter- of an extended system, and as a result, in a short time, action between the disk of planetesimals and the gaseous the solid material in the disk (i.e., planetesimals) will be disk around the star will cause the gaseous disk to become drained by accretion onto the central star. This implies eccentric which in turn results in the disk of solid material that either the disks around the stars of a binary system to precess. This precession prevents km-sized planetes- will not have enough material to form planets, or these imals to reach velocities that would accommodate their planets are formed in a very short time. As an example, accretion. However, interestingly, it can help objects of Müller & Kley (2012) have shown that for a system simi- the sizes of tens of kilometers and larger to successfully

13 Figure 2: The binary system of L1551 and its disks. Figure 3: A composite RGB frame of the binary GJ 86 using the F225W (blue), F275W (green), and F336W (red) filters. grow (Beauge et al 2010). The difficulties do not end here. A quick look at the spectral types of the stars of these close binaries indicates that Circumbinary planetary systems. in two of these systems, namely, GJ 86 and γ Cephei, Although the discovery of circumbinary planets (CBPs) one of the stellar components is an evolved star. In the γ had been previously announced around several eclipsing Cephei system, the primary star, which is also the planet- binaries (e.g. NN Ser, Beuermann et al 2010; UZ For, hosting component, is a 1.6 solar-mass K IV-III giant, and Potter et al 2011; HU Aqu, Qian et al 2011), the fact that in the system of GJ 86, the secondary star is a white dwarf all these binaries include post main sequence stars and, in (Fig. 3). The fact that the stars of these systems have some cases, the orbits of their planets are unstable (Wit- left the main sequence suggests that these stars have gone tenmyer et al 2012, Hinse et al 2012a&b, Gozdziewski et al through a period of mass-loss implying that their respec- 2012) did not attract the attention of planetary scientists, tive binaries, where the planets formed, must have had in particular within the context of planet formation. The smaller stellar separations in the past. The newly discov- success of the Kepler space telescope in detecting the 8 cur- ered planet around a star of the binary OGLE-2013-BLG- rently known circumbinary planets around main sequence 0341 where the binary semimajor axis is approximately stars, namely Kepler 16b (Doyle et al 2011), Kepler 34b 15 AU confirms this prediction. As a point of comparison, & 35b (Welsh et al 2012), Kepler 38b (Orosz et al 2012a), the separation of the two stars in the progenitor system of Kepler 47b&c (Orosz et al 2012b), Kepler 64b (Schwamb GJ 86 was 14.5 AU (Farihi et al 2013). Recent computa- et al 2013, Kostov et al 2013), and Kepler 413b (Kostov tional simulations suggest that in these systems, planet(s) et al 2014a&b), however, has made it certain that planet formed around the main sequence primary, and as a star of formation around binary star systems is robust and these the binary evolved, these planets interacted with one an- systems may host planets of a variety of sizes, in circumbi- other, with one ending up in its current orbit, and other nary orbits. planets being scattered out of the system. A survey of the currently known CBPs points to two inter- In brief, formation of circumstellar planets in close binary esting characteristics of these objects: 1) the close proxim- systems is still unresolved. It is believed that these planets ity of their orbits to the boundary of orbital stability, and form similarly to those around single stars. However, the 2) the apparent lack of CBPs around very short-period bi- perturbation of the stellar companion makes the matter naries. Although the current population of CBPs presents much more complicated. It also seems that these plan- only a small sample, these characteristics of CBPs are sig- ets formed in smaller disks and perhaps even on short nificant in the sense that they are interconnected and re- time scales, two other issues that add to the complexities. flect the effect of underlying physics with roots in the dy- Many efforts are currently made to uncover these myster- namical evolution of planet-forming circumbinary disks. ies which can also shed more light on the planet formation As one would expect, the orbit of an object around a bi- process in general. nary star can be perturbed by the stars of the binary. This

14 perturbation depends, naturally, on the size of the binary and the masses of its stars. As shown by Dvorak (1986), Dvorak et al (1989), and Holman & Wiegert (1999), these properties of a binary define a circumbinary region interior to which the orbit of an object will become unstable. An immediate implication of such a stability boundary is that circumbinary disk material is removed from the immediate neighborhood of the two stars and a cavity is created in the center of the disk. Planet formation will then occur at the parts of the disk that are exterior to this cavity. Planet formation in circumbinary orbits Soon after the discovery of the first Kepler CBP (Kepler 16b), it was noted that this planet is only 12% away from the boundary of orbital stability. This finding prompted theorists to investigate the possibility of the formation of CBPs close to the binary stability limit (Meschiari 2012, Paardekooper Figure 4: Graph of the orbital stability of the circumbi- et al 2012, Marzari et al 2013, Dunhill & Alexander 2013, nary planet of Kepler 34 system using the maximum ec- Pierens & Nelson 2013). Results, however, were some- centricity criterion. The color coding represent the maxi- what disappointing as simulations indicated that the re- mum value of the orbital eccentricity of the planet during gion around the stability limit is an unfriendly environ- an integration. Any object for which e = 1 was considered ment where the orbits of planetesimals are highly excited unstable. As shown here, there are islands of instability and their collisions are destructive. corresponding to some n : 1 mean-motion resonances. The The orbital excitation of bodies in regions around the sta- planet Kepler 34b is shown by the yellow circle. bility limit can be attributed to the interactions of these objects with n : 1 mean-motion resonances with the cen- objects would be that of Saturn or smaller (consistent with tral binary. Around a binary, these resonances create is- the masses of the current Kepler CBPs). lands of instability where the orbital eccentricity of an object is highly increased. As a result, either this object Despite the success of the model by Pierens & Nelson is scattered out of the system, or it collides with the cen- (2008) in predicting the locations of the orbits of CBPs and tral stars. In a circumbinary disk of planetesimals, the in- their masses, the application of this model to the currently crease in the orbital eccentricities of these bodies increases known Kepler CBP-hosting binaries did not reproduce the their relative velocities causing their collisions to result in orbits of their planets (Pierens & Nelson 2013). While breakage and shattering. Figure 4 shows these resonances the results of their recent simulations clearly indicate the for the CBP system of Kepler 34. inward migration of planets followed by trapping in stable orbits, the final orbits of these objects did not match The fact that CBPs cannot form in orbits close to the those obtained from observation (planets stopped prior to boundary of stability implies that these objects must have reaching their current orbits). The latter motivated Kley formed at farther distances and migrated to their current & Haghighipour (2014) to examine whether variations in orbits. Planet migration in and around binary stars has the energy and thermal structure of the disk, as well as its been the subject of studies for more than a decade. The boundary conditions would resolve this problem. Recall two pioneering works on this topic are those of Kley & that in their simulations, Pierens & Nelson (2013) consid- Burkert (2000) who studied the migration of planets in a ered a locally isothermal disk with a closed inner bound- circumprimary disk in a binary system, and Nelson (2003) ary. Kley & Haghighipour considered a fully radiative disk who studied planet migration in a circumbinary nebula. with an open inner boundary (allowing mass to flow from In an article in 2008 (prior to the detection of planets in the disk onto the central binary), and studied the dynam- circumbinary orbits), Pierens & Nelson revisited planet ical evolution of CBP Kepler 38b in a circumbinary disk. migration in circumbinary disks and showed that in an These authors were able to show that the planet contin- isothermal disk with a closed inner boundary (i.e., no flow uously migrates inward until it reaches the inner cavity of disk material onto the central binary), these planets can created by the binary. The strong drop in the disk surface be trapped in orbits close to the stability limit. Results density within the central cavity and the resulting positive of the simulations by these authors also suggested that density gradient act as a planet trap (Figure 5). Here the the trapping mechanism is more efficient for planets with negative Lindblad torques are balanced by positive coro- masses smaller than that of Jupiter implying that Jupiter- tation torques. As a result, the planet stops its inward mass CBPs would be rare and the dominant mass of these migration in this region. These authors were able to show

15 that in all their simulations, the planet stops at approx- the planet plunges into the central binary. Simulations of imately the same distance from the binary implying that planet-planet interactions have shown that CBPs can also the outcome of the migration process does not depend on be scattered into inclined orbits. These inclined planets the history of the system and is determined solely by the may transit the central binary occasionally or may not physical parameters of the disk such as its scale-height transit at all. Efforts are currently underway to develop and viscosity. Recently these authors have extended their methods for detecting these inclined CBPs. analysis to the system of Kepler 34 for which their sim- References: ulations have shown that similar results are obtained for Artymowicz, P. & Lubow, S. H. 1994, ApJ, 421, 651 eccentric binaries. Beauge, C. et al. 2010, MNRAS, 408, 503 Beuermann, K. et al. 2010, A&A, 521, L60 Bieging, J. H. & Cohen, M. 1985, ApJ, 289, L8 Chauvin, G. et al. 2011, A&A, 528, A8 Correia, A. C. M. et al, 2008, A&A, 479, 271 Doyle, L. R. et al, 2011, Science, 333, 1602 Dvorak, R. 1986, A&A, 167, 379 Dvorak, R. ET AL, 1989, A&A, 226, 335 Dunhill, A. C. & Alexander, R. D., 2013, MNRAS, 435, 2328 Eggenberger, A. et al, 2003, ASP Conf. Ser. 294, 43 Endl, M., et al, 2011, AIP Conf. Ser. 1331, 88 Farihi, J. et al. 2013, MNRAS, 430, 652// Gozdziewski, K. et al, 2012, MNRAS, 425, 930 Gould A. et al. 2014, Science, 345, p6 Haghighipour, N. 2006, ApJ, 644, 543 Haghighipour, N., 2010, Book: Planets in Binary Star Systems, (Springer, New York) Haghighipour N. & Kaltenegger L. 2013, ApJ, 777, 166 Hatzes, A. P. 2013, ApJ, 770, 133 Hatzes, A. P. et al, 2003, ApJ, 599, 1383 Hinse, T. C. et al, 2012, AJ, 144, 34 Hinse, T. C. et al, 2012, MNRAS, 420, 3609 Holman M. J. & Wiegert P. A. 1999, AJ, 117, 621 Jang-Condell, H. et al, 2008, ApJ, 683, L191 Kaltenegger L. & Haghighipour, N. 2013, ApJ, 777, 165 Kley, W. & Burkert, A., 2000, ASP Conf. Ser. 219, 189 Figure 5: Two-dimensional density structure of a radiative Kley, W. & Haghighipour, N., 2014, A&A, 564, A72 disk around the binary system of Kepler 38. The central Kostov, V. B. et al, 2013, ApJ, 770, 52 white region is the interior region of the disk excluded in Kostov, V. B. et al, 2014a, ApJ, 784, 14 the simulations. The stars of the binary are shown by Kostov, V. B. et al, 2014b, ApJ, 787, 93 Kraus, A. L. et al, 2012, ApJ, 745, 12 gray circles in this region. The circumbinary boundary of Marzari, F. & Scholl, H. 2000, ApJ, 543, 328 planetary stability can be seen as the black region. The Marzari, F. et al, 2013, A&A, 553, A71 orbit of the planet, Kepler 38b, is shown in dark brown Meschiari, S. 2012, APJ, 761, L7 and, as expected, is slightly outside the stability boundary. Müller, T. W. A. & Kley, W. 2012, A&A, 539, A18 Müller, T. W. A. & Haghighipour, N. 2014, ApJ, 782, 26 The planet is on this orbit just below 9:00 o’clock. Muterspaugh, M. W. et al, 2010, AJ, 140, 1657 Nelson, R. P., 2003, MNRAS, 345, 233 To summarize, it is now accepted that planet formation Orosz J. A. et al, 2012a, ApJ, 758, 87 Orosz J. A. et al, 2012b, Science, 337, 1511 around binaries begins and continues similar to that around Paardekooper, S.-J. et al,2008, MNRAS, 386, 973 single stars. Planets form at large distances from the bi- Paardekooper, S.-J. et al, 2012, ApJL, 754, L16 nary, where the perturbing effects of the stars are negligi- Pierens, A. & Nelson, R. P., 2013, A&A, 556, A134 ble and the disk carries similar structures as those around Pierens, A. & Nelson, R. P., 2008, A&A, 483, 633 Potter, S. B. et al. 2011, MNRAS, 416, 2202 single stars. The existence of multi-CBP systems such Qian, S.-B. et al, 2011, MNRAS, 414, L16 as Kepler 47 strongly indicates that circumbinary planets Queloz, D. et al, 2000, A&A, 354, 99 form in multiples and may undergo planet-planet interac- Rodriguez, L. F. et al. 1998, Nature, 395, 355 tion. Subsequent migration of planets combined with their Schwamb, M. E. et al, 2013, ApJ, 768, 127 Thebault, P. et al, 2004, A&A, 427, 1097 mutual interactions (planet-planet scattering) as well as Thebault, P. et al, 2006, Icarus, 183, 193 their interactions with n : 1 resonances are the main fac- Thebault, P. & Haghighipour, N. 2014, tors in determining the final orbital configuration of CBPs. Welsh, W. F. et al, 2012, Nature, 481, 475 Wittenmyer, R. A. et al, 2012, MNRAS, 419, 3258 While n : 1 resonances excite the orbits of migrating plan- Xie, J-i. & Zhou, J-L. 2009, ApJ, 698, 2066 ets, the planet-disk interaction damps the planet’s orbital Xie, J-W. et al, 2010, ApJ, 708, 1566 eccentricity. Migration stops when the damping effect of Zsom, A. et al. A&A, 527, A10 the disk overcomes the perturbing effect of resonances, or Zucker, S. 2004, A&A, 426, 695

16 Abstracts of recently accepted papers

A common column density threshold for scattering at 3.6 µm and water-ice in molecular clouds M. Andersen1,2, W. F. Thi1, J. Steinacker1,3 and N. Tothill4 1 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble, France 2 Aix Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille, UMR 7326, 13388, Marseille, France 3 Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany 4 University of Western Sydney, Locked Bag 1797, Penrith 2751 NSW, Australia E-mail contact: morten.andersen at lam.fr Context: Observations of scattered light in the 1-5 µm range have revealed dust grains in molecular cores with sizes larger than commonly inferred for the diffuse interstellar medium. It is currently unclear whether these grains are grown within the molecular cores or are an ubiquitous component of the interstellar medium. Aims: We investigate whether the large grains necessary for efficient scattering at 1-5 µm are associated with the abundance of water-ice within molecular clouds and cores. Methods: We combined water-ice abundance measurements for sight lines through the Lupus IV molecular cloud complex with measurements of the scattered light at 3.6 µm for the same sight lines. Results: We find that there is a similar threshold for the cores in emission in scattered light at 3.6 µm ( τ9.7 =0.15±0.05, AK =0.4 ± 0.2) as water-ice (τ9.7 =0.11 ± 0.01, AK =0.19 ± 0.04) and that the scattering efficiency increases as the relative water-ice abundance increases. The ice layer increases the average grain size, which again strongly increases the albedo. Conclusions: The higher scattering efficiency is partly due to layering of ice on the dust grains. Although the layer can be relatively thin it can enhance the scattering substantially. Accepted by A&A Letters http://arxiv.org/pdf/1407.5836

Probing the Terrestrial Regions of Planetary Systems: Warm Debris Disks with Emis- sion Features Nicholas P. Ballering1, George H. Rieke1, András Gáspár1 1 Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA E-mail contact: ballerin at email.arizona.edu Observations of debris disks allow for the study of planetary systems, even where planets have not been detected. However, debris disks are often only characterized by unresolved infrared excesses that resemble featureless blackbodies, and the location of the emitting dust is uncertain due to a degeneracy with the dust grain properties. Here we characterize the Spitzer IRS spectra of 22 debris disks exhibiting 10 µm silicate emission features. Such features arise from small warm dust grains, and their presence can significantly constrain the orbital location of the emitting debris. We find that these features can be explained by the presence of an additional dust component in the terrestrial zones of the planetary systems, i.e. an exozodiacal belt. Aside from possessing exozodiacal dust, these debris disks are not particularly unique; their minimum grain sizes are consistent with the blowout sizes of their systems, and their brightnesses are comparable to those of featureless warm debris disks. These disks are in systems with a range of ages, although the older systems with features are found only around A-type stars. The features in young systems may be signatures of terrestrial planet formation. Analyzing the spectra of unresolved debris disks with emission features may be one of the simplest and most accessible ways to study the terrestrial regions of planetary systems. Accepted by ApJ http://arxiv.org/pdf/1407.7547

17 Anomalous Accretion Activity and the Spotted Nature of the DQ Tau Binary System Jeffrey S. Bary1,2 and Michael S. Petersen1,3 1 Colgate University, Department of Physics & Astronomy, 13 Oak Drive, Hamilton, NY 13346, USA 2 Visiting Astronomer, Laboratoire AIM Paris-Saclay, CEA/Irfu UniversitéParis-Diderot CNRS/INSU, 91191 Gif- sur-Yvette, France 3 University of Massachusetts, Department of Astronomy, 710 North Pleasant Street, Amherst, MA 01003, USA E-mail contact: mpete0 at astro.umass.edu We report the detection of an anomalous accretion flare in the tight eccentric pre-main-sequence binary system DQ Tau. In a multi-epoch survey consisting of randomly acquired low to moderate resolution near-infrared spectra obtained over a period of almost ten years, we detect a significant and simultaneous brightening of four standard accretion indicators (Ca ii infrared triplet, the Paschen and Brackett series H i lines, and He i 1.083 µm), on back-to-back nights (φ = 0.372, 0.433) with the flare increasing in strength as the system approached apastron (φ = 0.5). The mass accretion rate measured for the anomalous flare is nearly an order of magnitude stronger than the average quiescent rate. While previous observations established that frequent, periodic accretion flares phased with periastron passages occur in this system, these data provide evidence that orbitally-modulated accretion flares occur near apastron, when the stars make their closest approach to the circumbinary disk. The timing of the flare suggests that this outburst is due to interactions of the stellar cores (or the highly truncated circumstellar disks) with material in non-axisymmetric structures located at the inner edge of the circumbinary disk. We also explore the optical/infrared spectral type mismatch previously observed for T Tauri stars and successfully model the shape of the spectra from 0.8 to 1.0 µm and the strengths of the TiO and FeH bands as manifestations of large cool spots on the surfaces of the stellar companions in DQ Tau. These findings illustrate that a complete model of near-infrared spectra of many T Tauri stars must include parameters for spot filling factors and temperatures. Accepted by ApJ http://arxiv.org/pdf/1407.3309

Physical and orbital properties of β Pictoris b M. Bonnefoy1, G.-D. Marleau2, R. Galicher3, H. Beust1, A.-M. Lagrange1, J.-L. Baudino3, G. Chauvin1, S. Borgniet1, N. Meunier1, J. Rameau1, A. Boccaletti3, A. Cumming4, C. Helling5, D. Homeier6, F. Allard6, P. Delorme1 1 UniversitéGrenoble Alpes, IPAG, F-38000 Grenoble, France. CNRS, IPAG, F-38000 Grenoble, France 2 Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany 3 LESIA, CNRS, Observatoire de Paris, Univ. Paris Diderot, UPMC, 5 place Jules Janssen, 92190 Meudon, France 4 Department of Physics, McGill University, 3600 rue University, Montréal, Québec H3A 2T8, Canada 5 SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK 6 CRAL, UMR 5574, CNRS, Universitéde Lyon, Ecole´ Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon, France E-mail contact: bonnefmi at obs.ujf-grenoble.fr The intermediate-mass star β Pictoris is known to be surrounded by a structured edge-on debris disk within which a gas giant planet was discovered orbiting at 8–10 AU. The physical properties of β Pic b were previously inferred from broad and narrow-band 0.9–4.8 µm photometry. We used commissioning data of the Gemini Planet Imager (GPI) to obtain new astrometry and a low-resolution (R∼35–39) J-band (1.12–1.35 µm) spectrum of the planet. We find that the planet has passed the quadrature. We constrain its semi-major axis to ≤ 10 AU (90% prob.) with a peak at +0.4 8.9−0.6 AU. The joint fit of the planet astrometry and the most recent radial velocity measurements of the star yields a planet’s dynamical mass ≤ 20 MJup (greater than 96% prob.). The extracted spectrum of β Pic b is similar to those of +1 young L1−1.5 dwarfs. We use the spectral type estimate to revise the planet luminosity to log(L/L⊙)= −3.90 ± 0.07. The 0.9–4.8 µm photometry and spectrum are reproduced for Teff = 1650 ± 150 K and a log g lower than 4.7 dex by 12 grids of PHOENIX-based and LESIA atmospheric models. If we adopt the most recent system age estimate (21±4 Myr), the bolometric luminosity and the constraints on the dynamical mass of β Pic b are only reproduced by warm- −1 and hot-start tracks with initial entropies Si greater than 10.5 kB baryon . Such initial conditions may result from an inefficient accretion shock and/or a planetesimal density at formation higher than in the classical core accretion

18 model. Considering a younger age for the system or a conservative formation time for β Pic b does not change these conclusions. Accepted by A&A Letters http://arxiv.org/pdf/1407.4001

The disk around the brown dwarf KPNO Tau 3 Hannah Broekhoven-Fiene1, Brenda Matthews2,1, Gaspard Duchêne3,4, James Di Francesco2,1, Aleks Scholz5, Antonio Chrysostomou6 and Ray Jayawardhana7 1 Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 3P6, Canada 2 Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC, V9E 2E7, Canada 3 Department of Astronomy, University of California at Berkeley, Hearst Field Annex, B-20, Berkeley CA 94720-3411, USA 4 UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique (IPAG), UMR 5274, F-38041 Grenoble, France 5 School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK 6 Joint Astronomy Centre, 660 North Aóhoku Place, University Park, Hilo, HI 96720, USA 7 Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada E-mail contact: broekhov at uvic.ca We present submillimeter observations of the young brown dwarfs KPNO Tau 1, KPNO Tau 3, and KPNO Tau 6 at 450 µm and 850 µm taken with the Submillimeter Common-User Bolometer Array on the James Clerke Maxwell Telescope. KPNO Tau 3 and KPNO Tau 6 have been previously identified as Class II objects hosting accretion disks, whereas KPNO Tau 1 has been identified as a Class III object and shows no evidence of circumsubstellar material. Our −4 3 σ detection of cold dust around KPNO Tau 3 implies a total disk mass of (4.0 ± 1.1) × 10 M⊙ (assuming a gas to −4 dust ratio of 100:1). We place tight constraints on any disks around KPNO Tau 1 or KPNO Tau 6 of < 2.1 × 10 M⊙ −4 and < 2.7 × 10 M⊙, respectively. Modeling the spectral energy distribution of KPNO Tau 3 and its disk suggests the disk properties (geometry, dust mass, and grain size distribution) are consistent with observations of other brown dwarf disks and low-mass T-Tauri stars. In particular, the disk-to-host mass ratio for KPNO Tau 3 is congruent with the scenario that at least some brown dwarfs form via the same mechanism as low-mass stars. Accepted by ApJ http://arxiv.org/pdf/1407.0700

The Taurus Boundary of Stellar/Substellar (TBOSS) Survey I: far-IR disk emission measured with Herschel J. Bulger1,2, J. Patience1,2, K. Ward-Duong2,4, C. Pinte3, H. Bouy4, F. Ménard3, and J.-L. Monin5 1 School of Physics, University of Exeter, Exeter, EX4 4QL, UK 2 School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281, USA 3 Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile 4 Centro de Astrobiolog´ıa- Depto. Astrof´ısica (CSIC- INTA), ESAC Campus, PO Box 78, E-28691 Villanueva de la Cañada, Spain 5 UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Greno- ble, F-38041, France E-mail contact: jbulger1 at asu.edu With Herschel/PACS 134 low mass members of the Taurus star-forming region spanning the M4-L0 spectral type range and covering the transition from low mass stars to brown dwarfs were observed. Combining the new Herschel results with other programs, a total of 150 of the 154 M4-L0 Taurus members members have observations with Herschel. Among the 150 targets, 70 µm flux densities were measured for 7 of the 7 ClassI objects, 48 of the 67 ClassII members, and 3 of the 76 ClassIII targets. For the detected ClassII objects, the median 70um flux density level declines with spectral type, however, the distribution of excess relative to central object flux density does not

19 change across the stellar/substellar boundary in the M4-L0 range. Connecting the 70 µm TBOSS values with the results from K0-M3 ClassII members results in the first comprehensive census of far-IR emission across the full mass spectrum of the stellar and substellar population of a star-forming region, and the median flux density declines with spectral type in a trend analogous to the flux density decline expected for the central objects. SEDs were constructed for all TBOSS targets covering the optical to far-IR range and extending to the submm/mm for a subset of sources. Based on an initial exploration of the impact of different physical parameters; inclination, scale height and flaring have the largest influence on the PACS flux densities. From the 24 µm to 70 µm spectral index of the SEDs, 5 new candidate transition disks were identified. The steep 24 µm to 70 µm slope for a subset of 8 TBOSS targets may be an indication of truncated disks in these systems.Two examples of mixed pair systems that include secondaries with disks were measured. Finally, comparing the TBOSS results with a Herschel study of Ophiuchus brown dwarfs reveals a lower fraction of disks around the Taurus substellar population. Accepted by A&A http://arxiv.org/pdf/1407.4802

A high resolution study of complex organic molecules in hot cores Hannah Calcutt1, Serena Viti1, Claudio Codella2, Maria T. Beltrán2, Francesco Fontani2, and Paul M. Woods1,3 1 Department of Physics and Astronomy, University College London, WC1E 6BT, London, UK 2 INAF, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze, Italy 3 Astrophysics Research Centre, School of Mathematics & Physics, Queen’s University Belfast, Belfast BT7 1NN, UK E-mail contact: hcalcutt at star.ucl.ac.uk We present the results of a line identification analysis using data from the IRAM Plateau de Bure Inferferometer, focus- ing on six massive star-forming hot cores: G31.41+0.31, G29.96−0.02, G19.61−0.23, G10.62−0.38, G24.78+0.08A1 and G24.78+0.08A2. We identify several transitions of vibrationally excited methyl formate (HCOOCH3) for the first time in these objects as well as transitions of other complex molecules, including ethyl cyanide (C2H5CN), and isocyanic acid (HNCO). We also postulate a detection of one transition of glycolaldehyde (CH2(OH)CHO) in two new hot cores. We find G29.96−0.02, G19.61−0.23, G24.78+0.08A1 and 24.78+0.08A2 to be chemically very similar. G31.41+0.31, however, is chemically different: it manifests a larger chemical inventory and has significantly larger column densities. We suggest that it may represent a different evolutionary stage to the other hot cores in the sample, or it may surround a star with a higher mass. We derive column densities for methyl formate in G31.41+0.31, 17 −2 using the rotation diagram method, of 4 ×10 cm and a Trot of ∼170 K. For G29.96−0.02, G24.78+0.08A1 and G24.78+0.08A2, glycolaldehyde, methyl formate and methyl cyanide all seem to trace the same material and peak at roughly the same position towards the dust emission peak. For G31.41+0.31, however, glycolaldehyde shows a different distribution to methyl formate and methyl cyanide and seems to trace the densest, most compact inner part of hot cores. Accepted by MNRAS http://arxiv.org/pdf/1407.1661

Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength gas and dust observations A. Carmona1, C. Pinte2,1, W.F. Thi1, M. Benisty1, F. Ménard2,1, C. Grady3,4,5, I. Kamp6, P. Woitke7, J. Olofsson8, A. Roberge5, S. Brittain9, G. Duchêne10,1, G. Meeus11, C. Martin-Za¨ıdi1, B. Dent12, J.B. Le Bouquin1 and J.P. Berger13,1 1 UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Greno- ble, F-38041, France 2 UMI-FCA, CNRS / INSU France (UMI 3386), and Departamento de Astronom´ıa, Universidad de Chile, Santiago, Chile 3 Eureka Scientific, 2452 Delmer, Suite 100, Oakland CA 96002, USA 4 ExoPlanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771,

20 USA 5 Goddard Center for Astrobiology, Goddard Space Flight Center, Greenbelt, MD 20771, USA 6 Kapteyn Astronomical Institute, P.O. Box 800, 9700 AV Groningen, The Netherlands 7 SUPA, School of Physics and Astronomy, University of St Andrews, KY16 9SS, UK 8 Max Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany 9 Department of Physics & Astronomy, 118 Kinard Laboratory, Clemson University, Clemson, SC 29634, USA 10 Astronomy Department, University of California, Berkeley, CA 94720-3411, USA 11 Departamento de F´ısica Teórica, Universidad Autonoma de Madrid, Campus Cantoblanco, Spain 12 Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura 763-0355, Santiago, Chile 13 European Southern Observatory, Alonso de Córdova, 3107 Vitacura, Chile E-mail contact: andres.carmona at uam.es Context. Constraining the gas and dust disk structure of transition disks, particularly in the inner dust cavity, is a crucial step toward understanding the link between them and planet formation. HD 135344B is an accreting (pre-) transition disk that displays the CO 4.7 µm emission extending tens of AU inside its 30 AU dust cavity. Aims. We constrain HD 135344B’s disk structure from multi-instrument gas and dust observations. Methods. We used the dust radiative transfer code MCFOST and the thermochemical code ProDiMo to derive the disk structure from the simultaneous modeling of the spectral energy distribution (SED), VLT/CRIRES CO P(10) 4.75 µm, Herschel/PACS [OI] 63 µm, Spitzer-IRS, and JCMT 12CO J=3-2 spectra, VLTI/PIONIER H-band visibilities, and constraints from (sub-)mm continuum interferometry and near-IR imaging. Results. We found a disk model able to describe the current gas and dust observations simultaneously. This disk has the following structure. (1) To simultaneously reproduce the SED, the near-IR interferometry data, and the CO ro-vibrational emission, refractory grains (we suggest carbon) are present inside the silicate sublimation radius (0.08 100 to account for the 870 µm continuum upper limit and the CO P(10) line flux. (5) The gas-to-dust ratio in the outer disk (30

The Magnetic Field of Cloud 3 in L204 Lauren R. Cashman1 and D.P. Clemens1 1 Institute for Astrophysical Research and Boston University, 725 Commonwealth Ave, Boston, MA 02215, USA E-mail contact: lcashman at bu.edu The L204 dark cloud complex is a nearby filamentary structure in Ophiuchus North that has no signs of active star formation. Past studies show that L204 is interacting with the nearby runaway O star, ζ Oph, and hosts a magnetic field that is coherent across parsec-length scales. Near-infrared H-band (1.6 µm) linear polarization measurements were obtained for 3,896 background stars across a 1◦ × 1.◦5 region centered on the dense Cloud 3 in L204, using the Mimir near-infrared instrument on the 1.8m Perkins Telescope. Analysis of these observations reveals both large-scale properties and small-scale changes in the magnetic field direction in Cloud 3. In the northern and western ζ Oph facing regions of the cloud, the magnetic field appears to be pushed up against the face of the cloud. This may indicate that the UV flux from ζ Oph has compressed the magnetic field on the western edge of L204. The plane-of-sky magnetic field strength is estimated to be ∼11–26 µG using the Chandrasekhar-Fermi method. The polarimetry data also reveal that the polarization efficiency (PE = PH/AV) steadily decreases with distance from ζ Oph (−0.09 ± 0.03% −1 −1 mag pc ). Additionally, power-law fits of PE versus AV for localized samples of probe stars show steeper negative

21 indices with distance from ζ Oph. Both ﬁndings highlight the importance of external illumination, here from ζ Oph, in aligning dust grains to embedded magnetic ﬁelds. Accepted by ApJ http://arxiv.org/pdf/1407.3279

Line Profiles of Cores within Clusters. III. What is the most reliable tracer of core collapse in dense clusters? Roxana-Adela Chira1,2,3, Rowan J. Smith1, Ralf S. Klessen1, Amelia M. Stutz3 and Rahul Shetty1 1 Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany 2 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching b. München, Germany 3 Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany E-mail contact: rox.chira at gmail.com Recent observational and theoretical investigations have emphasised the importance of filamentary networks within molecular clouds as sites of star formation. Since such environments are more complex than those of isolated cores, it is essential to understand how the observed line profiles from collapsing cores with non-spherical geometry are affected by filaments. In this study, we investigate line profile asymmetries by performing radiative transfer calculations on hydrodynamic models of three collapsing cores that are embedded in filaments. We compare the results to those that are expected for isolated cores. We model the five lowest rotational transition line (J = 1-0, 2-1, 3-2, 4-3, and 5-4) of + + 13 + both optically thick (HCN, HCO ) as well as optically thin (N2H , H CO ) molecules using constant abundance laws. We find that less than 50% of simulated (1-0) transition lines show blue infall asymmetries due to obscuration by the surrounding filament. However, the fraction of collapsing cores that have a blue asymmetric emission line profile rises to 90% when observed in the (4-3) transition. Since the densest gas towards the collapsing core can excite higher rotational states, upper level transitions are more likely to produce blue asymmetric emission profiles. We conclude that even in irregular, embedded cores one can trace infalling gas motions with blue asymmetric line profiles of optically thick lines by observing higher transitions. The best tracer of collapse motions of our sample is the (4-3) transition of HCN, but the (3-2) and (5-4) transitions of both HCN and HCO+ are also good tracers. Accepted by MNRAS http://arxiv.org/pdf/1402.5279

Trigonometric Parallaxes of Star Forming Regions in the Perseus Spiral Arm Y.K. Choi1,2, K. Hachisuka3, M.J. Reid4, Y. Xu5, A. Brunthaler1, K.M. Menten1, and T.M. Dame4 1 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121 Bonn, Germany 2 Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348, Korea 3 Shanghai Astronomical Observatory, Chinese Academy of Science, Shanghai, 200030, China 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 5 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China E-mail contact: ykchoi at kasi.re.kr We report trigonometric parallaxes and proper motions of water masers for 12 massive star forming regions in the Perseus spiral arm of the Milky Way as part of the Bar and Spiral Structure Legacy (BeSSeL) Survey. Combining our results with 14 parallax measurements in the literature, we estimate a pitch angle of 9.◦9 ± 1.◦5 for a section of the Perseus arm. The three-dimensional Galactic peculiar motions of these sources indicate that on average they are moving toward the Galactic center and slower than the Galactic rotation. Accepted by ApJ http://arxiv.org/pdf/1407.1609

22 The ALMA view of the protostellar system HH212 - The wind, the cavity, and the disk C. Codella1, S. Cabrit2,3, F. Gueth4, L. Podio1, S. Leurini5, R. Bachiller6, A. Gusdorf2, B. Lefloch3, B. Nisini7, M. Tafalla6 and W. Yvart2 1 INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy 2 LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole´ Normale Supérieure, 61 Av. de l’Observatoire, 75014 France 3 UJF-Grenoble1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, 38041, France 4 IRAM, 300 rue de la Piscine, 38406 Saint Martin d’Hères, France 5 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany 6 IGN, Observatorio Astronómico Nacional, Alfonso XIII 3, 28014, Madrid, Spain 7 INAF, Osservatorio Astronomico di Roma, via di Frascati 33, 00040, Monte Porzio Catone, Italy E-mail contact: codella at arcetri.astro.it Context: Because it is viewed simply edge-on, the HH212 protostellar system is an ideal laboratory for studying the interplay of infall, outflow, and rotation in the earliest stages of low-mass star formation. Aims: We wish to exploit the unmatched combination of high angular resolution, high sensitivity, high-imaging fidelity, and spectral coverage provided by ALMA to shed light on the complex kinematics of the innermost central regions of HH212. Methods: We mapped the inner 10arcsec (4500 AU) of the HH212 system at ≃ 0.5 arcsec resolution in several molecular tracers and in the 850 µm dust continuum using the ALMA interferometer in band 7 in the extended configuration of the Early Science Cycle 0 operations. Results: Within a single ALMA spectral set-up, we simultaneously identify all the crucial ingredients known to be involved in the star formation recipe namely: (i) the fast, collimated bipolar SiO jet driven by the protostar, (ii) the large-scale swept-up CO outflow, (iii) the flattened rotating and infalling envelope, with bipolar cavities carved by the outflow (in C17O(3–2)), and (iv) a rotating wide-angle flow that fills the cavities and surrounding the axial jet (in C34S(7–6)). In addition, the compact high-velocity C17O emission (± 1.9–3.5 km s−1 from systemic) shows a velocity gradient along the equatorial plane consistent with a rotating disk of ≃ 0.2 arcsec = 90 AU around a ≃ 0.3 ± 0.1M⊙ source. The rotating disk is possibly Keplerian. Conclusions: HH212 is the third Class 0 protostar with possible signatures of a Keplerian disk of radius ≥ 30AU. The warped geometry in our CS data suggests that this large Keplerian disk might result from misaligned magnetic and rotation axes during the collapse phase. The wide-angle CS flow suggests that disk winds may be present in this source. Accepted by Astronomy & Astrophysics Letters http://arxiv.org/pdf/1407.6229

High D2O/HDO ratio in the inner regions of the low-mass protostar NGC1333 IRAS2A Audrey Coutens1,2, Jes K. Jørgensen1,2, Magnus V. Persson3, Ewine F. van Dishoeck3,4, Charlotte Vastel5,6 and Vianney Taquet7 1 Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark 2 Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark 3 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands 4 Max-Planck-Institut f¨ur Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany 5 Universit´ede Toulouse, UPS-OMP, IRAP, Toulouse, France 6 CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France 7 NASA Postdoctoral Program Fellow, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770, USA E-mail contact: acoutens at nbi.dk Water plays a crucial role both in the interstellar medium and on Earth. To constrain its formation mechanisms and its evolution through the star formation process, the determination of the water deuterium fractionation ratios

23 is particularly suitable. Previous studies derived HDO/H2O ratios in the warm inner regions of low-mass protostars. We here report a detection of the D2O 11,0–10,1 transition toward the low-mass protostar NGC1333 IRAS2A with the Plateau de Bure interferometer: this represents the first interferometric detection of D2O – and only the second solar-type protostar for which this isotopologue is detected. Using the observations of the HDO 54,2–63,3 transition simultaneously detected and three other HDO lines previously observed, we show that the HDO line fluxes are well reproduced with a single excitation temperature of 218±21K and a source size of ∼0.5”. The D2O/HDO ratio is −2 18 −3 ∼(1.2±0.5) × 10 , while the use of previous H2 O observations give an HDO/H2O ratio of ∼(1.7±0.8) × 10 , i.e. a factor of 7 lower than the D2O/HDO ratio. These results contradict the predictions of current grain surface chemical models and indicate that either the surface deuteration processes are poorly understood or that both sublimation of grain mantles and water formation at high temperatures (≥230 K) take place in the inner regions of this source. In the second scenario, the thermal desorption of the grain mantles would explain the high D2O/HDO ratio, while water formation at high temperature would explain significant extra production of H2O leading to a decrease of the HDO/H2O ratio. Accepted by ApJL http://arxiv.org/pdf/1407.6842

Pre-main sequence accretion and the formation of multiple populations in Globular Clusters Francesca D’Antona1, Paolo Ventura1, Thibaut Decressin1, Enrico Vesperini2, and Annibale D’Ercole3 1 INAF- Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio, Italy 2 Department of Astronomy, Indiana University, Bloomington, IN, USA 3 INAF- Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy E-mail contact: franca.dantona at gmail.com We investigate the viability of a model in which the chemical anomalies among Globular Cluster stars are due to accretion of gas onto the protostellar discs of low mass stars. This model has been suggested as a way to reduce the large initial cluster masses required by other models for the formation of multiple stellar generations. We numerically follow the evolution of the accreting stars, and we show that the structure of the seed star does not remain fully convective for the whole duration of the accretion phase. Stellar populations showing discrete abundances of helium in the core, that seem to be present in some clusters, might be formed with this mechanism only if accretion occurs before the core of the stars become radiative (within 2–3Myr) or if a thermohaline instability is triggered, to achieve full mixing after the accretion phase ends. We also show that the lithium abundances in accreted structures may vary by orders of magnitude in equal masses obtained by accreting diﬀerent masses. In addition, the same thermohaline mixing which could provide a homogeneous helium distribution down to the stellar center, would destroy any lithium surviving in the envelope, so that both helium homogeneity and lithium survival require that the accretion phase be limited to the ﬁrst couple of million years of the cluster evolution. Such a short accretion phase strongly reduces the amount of processed matter available, and reintroduces the requirement of an extremely large initial mass for the protocluster. Accepted by MNRAS http://arxiv.org/pdf/1407.2424

Accretion discs as regulators of stellar angular momentum evolution in the ONC and Taurus-Auriga Claire L. Davies1, Scott G. Gregory1 and Jane S. Greaves1 1 SUPA School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS E-mail contact: cd54 at st-andrews.ac.uk In light of recent substantial updates to spectral type estimations and newly established intrinsic colours, eﬀective temperatures, and bolometric corrections for pre-main sequence (PMS) stars, we re-address the theory of accretion- disc regulated stellar angular momentum (AM) evolution. We report on the compilation of a consistent sample of fully convective stars within two of the most well-studied and youngest, nearby regions of star formation: the Orion

24 Nebula Cluster (ONC) and Taurus-Auriga. We calculate the average specific stellar AM (j⋆) assuming solid body rotation, using surface rotation periods gathered from the literature and new estimates of stellar radii and ages. We use published Spitzer IRAC fluxes to classify our stars as Class II or Class III and compare their j⋆ evolution. Our results suggest that disc dispersal is a rapid process that occurs at a variety of ages. We find a consistent j⋆ reduction rate between the Class II and Class III PMS stars which we interpret as indicating a period of accretion disc-regulated AM evolution followed by near-constant AM evolution once the disc has dissipated. Furthermore, assuming our observed spread in stellar ages is real, we find the removal rate of j⋆ during the Class II phase is more rapid than expected by contraction at constant stellar rotation rate. A much more efficient process of AM removal must exist, most likely in the form of an accretion-driven stellar wind or other outflow from the star-disc interaction region or extended disc surface. Accepted by MNRAS http://arxiv.org/pdf/1407.6212

Testing the universality of the IMF with Bayesian statistics: young clusters Sami Dib1,2 1 Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen, Denmark 2 Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Copenhagen, Denmark E-mail contact: sdib at nbi.dk The universality of the stellar initial mass function (IMF) is tested using Bayesian statistics with a sample of eight young Galactic stellar clusters (IC 348, ONC, NGC 2024, NGC 6611, NGC 2264, ρ Ophiuchi, Chameleon I, and Taurus). We infer the posterior probability distribution function (pPDF) of the IMF parameters when the likelihood function is described by a tapered power law function, a lognormal distribution at low masses coupled to a power law at higher masses, and a multi-component power law function. The inter-cluster comparison of the pPDFs of the IMF parameters for each likelihood function shows that these distributions do not overlap within the 1σ uncertainty level. Furthermore, the most probable values of the IMF parameters for most of the clusters deviate substantially from their values for the Galactic field stellar IMF. We also quantify the effects of taking into account the completeness correction as well as the uncertainties on the measured masses. The inclusion of the former affects the inferred pPDFs of the slope of the IMF at the low mass end while considering the latter affects the pPDFs of the slope of the IMF in the intermediate- to high mass regime. As variations are observed in all of the IMF parameters at once and for each of the considered likelihood functions, even for completeness corrected samples, we argue that the observed variations are real and significant, at least for the sample of eight clusters considered in this work. The results presented here clearly show that the IMF is not universal. Accepted by MNRAS http://arxiv.org/pdf/1405.3287

The low mass star and sub-stellar populations of the 25 Orionis group Juan JoséDownes1,2, César Briceño1,3, Cecilia Mateu1,2, Jesús Hernández1, Anna Katherina Vivas3, Nuria Calvet4, Lee Hartmann4, Monika G. Petr-Gotzens5 and Lori Allen6 1 Centro de Investigaciones de Astronom´ıa, AP 264, Mérida 5101-A, Venezuela 2 Instituto de Astronom´ıa, UNAM, Ensenada, C.P. 22860, Baja California, México 3 Cerro Tololo Interamerican Observatory Casilla 603, La Serena, Chile 4 Department of Astronomy, University of Michigan, 825 Dennison Building, 500 Church Street, Ann Arbor, MI 48109, USA 5 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748, Garching bei München, Germany 6 National Optical Astronomy Observatories, 950 N. Cherry Ave. Tucson, AZ 85719, USA E-mail contact: jdownes at astrosen.unam.mx We present the results of a survey of the low mass star and brown dwarf population of the 25 Orionis group. Using optical photometry from the CIDA Deep Survey of Orion, near IR photometry from the Visible and Infrared Survey

25 Telescope for Astronomy and low resolution spectroscopy obtained with Hectospec at the MMT, we selected 1246 < < photometric candidates to low mass stars and brown dwarfs with estimated masses within 0.02 ∼ M/M⊙ ∼ 0.8 and spectroscopically confirmed a sample of 77 low mass stars as new members of the cluster with a mean age of ∼7 Myr. We have obtained a system initial mass function of the group that can be well described by either a Kroupa power-law function with indices α3 = −1.73 ± 0.31 and α2 =0.68 ± 0.41 in the mass ranges 0.03 ≤ M/M⊙ ≤ 0.08 and +0.02 0.08 ≤ M/M⊙ ≤ 0.5 respectively, or a Scalo log-normal function with coefficients mc =0.21−0.02 and σ =0.36 ± 0.03 in the mass range 0.03 ≤ M/M⊙ ≤ 0.8. From the analysis of the spatial distribution of this numerous candidate sample, we have confirmed the East-West elongation of the 25 Orionis group observed in previous works, and rule out a possible southern extension of the group. We find that the spatial distributions of low mass stars and brown dwarfs in 25 Orionis are statistically indistinguishable. Finally, we found that the fraction of brown dwarfs showing IR excesses is higher than for low mass stars, supporting the scenario in which the evolution of circumstellar discs around the least massive objects could be more prolonged. Accepted by MNRAS

SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps A. Duarte-Cabral1,2,3, S. Bontemps2,3, F. Motte4, A. Gusdorf5, T. Csengeri6, N. Schneider2,3 and F. Louvet4 1 School of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK 2 Univ. Bordeaux, LAB, UMR 5804, F-33270, Floirac, France 3 CNRS, LAB, UMR 5804, F-33270, Floirac, France 4 Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot,IRFU/Service d’Astrophysique, C.E.Saclay, Ormede- merisiers, 91191 Gif-sur-Yvette, France 5 LERMA, UMR 8112 du CNRS, Obs. de Paris, Ecole Normale Superieure, 24 rue Lhomond, F-75005, Paris, France 6 Max Planck Institute for Radioastronomy, Auf dem Hugel 69, 53121 Bonn, Germany E-mail contact: adc at astro.ex.ac.uk The SiO molecule is formed through interstellar shocks and is often used as a tracer of high-velocity shocks from protostellar outflows. However, recent studies have suggested that low-velocity shocks in the interstellar medium can be responsible for a significant amount of SiO emission observed in star-forming regions. We aim to investigate the existence of SiO emission that may or may not be associated with outflow shocks, within several massive dense clumps (MDCs), and explore how the SiO luminosities compare with the outflow properties estimated using CO. We used observations of SiO (2-1) from the Plateau de Bure Interferometre, towards a sample of six MDCs in Cygnus-X, and compared them to the CO high-velocity outflow emission, and to the velocity shears found in these regions. We find that most molecular outflows are detected in both SiO and CO, although there are some cases of CO outflows with no −1 SiO counterpart. The data also shows narrow line SiO emission (σvarv < 1.5 km s ) which, in some cases, appears to be unrelated to outflows. The kinematics of this narrow emission often differs from those found by other high- density tracers such as H13CO+, and its extent varies from rather compact (∼ 0.03pc) to widespread (∼ 0.2pc). We find that the least centrally concentrated clumps with the least massive protostellar cores have the most widespread narrow SiO emission. The fraction of the total SiO luminosity that is not associated with outflows is highly variable in the different MDCs (from 10% to 90%); this might be a problem when extrapolating outflow properties from SiO luminosities without resolving individual outflows. In line with previous evidence of SiO emission associated with low-velocity shocks, we propose an evolutionary picture to explain the existence and distribution of narrow SiO line profiles. In this scenario, the least centrally condensed MDCs are at an early stage where the SiO emission traces shocks from the large-scale collapse of material onto the MDC. This could be the case of CygX-N40, a MDC with a low-mass protostar at its centre, a weak outflow, and where 90% of the SiO emission is narrow and arises from the outskirts. As the MDC collapses, the SiO emission becomes more confined to the close surroundings of cores, tracing the post-shock material from the infalling MDC against the dense cores, such as in the small-scale converging flows of CygX-N3, N12, and N48. At later stages, when single massive protostars are formed, as for instance in CygX-N53 and N63, the SiO luminosity is largely dominated by powerful outflows, and the weaker narrow component shows perhaps the last remnants of the initial collapse. Accepted by Astronomy and Astrophysics http://arxiv.org/pdf/1407.6400

26 On the reliability of protostellar disc mass measurements and the existence of fragment- ing discs Michael M. Dunham1, Eduard I. Vorobyov2,3 and Héctor G. Arce4 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138, USA 2 Department of Astrophysics, University of Vienna, Vienna, 1180, Austria 3 Research Institute of Physics, Southern Federal University, Rostov-on-Don, 344090, Russia 4 Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520, USA} E-mail contact: mdunham at cfa.harvard.edu We couple non-magnetic, hydrodynamical simulations of collapsing protostellar cores with radiative transfer evolutionary models to generate synthetic observations. We then use these synthetic observations to investigate the extent to which a simple method for measuring protostellar disc masses used in the literature recovers the intrinsic masses of the discs formed in the simulations. We evaluate the effects of contamination from the surrounding core, partially resolving out the disc, optical depth, fixed assumed dust temperatures, inclination, and the dust opacity law. We show that the combination of these effects can lead to disc mass underestimates by up to factors of 2–3 at millimeter wavelengths and up to an order of magnitude or larger at submillimeter wavelengths. The optically thin portions of protostellar discs are generally cooler in the Class I stage than the Class 0 stage since Class I discs are typically larger and more optically thick, and thus more shielded. The observed disc mass distribution closely resembles the intrinsic distribution if this effect is taken into account, especially at millimeter wavelengths where optical depth effects are minimized. Approximately 50%–70% of protostellar discs observed to date with this method are consistent with the masses of the gravitationally unstable discs formed in the simulations, suggesting that at least some protostellar discs are likely sufficiently massive to fragment. We emphasize key future work needed to confirm these results, including assembling larger, less biased samples, and using molecular line observations to distinguish between rotationally supported, Keplerian discs and magnetically supported pseudodiscs. Accepted by MNRAS http://arxiv.org/pdf/1407.6955

High angular resolution 7 mm images toward the UC HII region W3(OH) Sergio A. Dzib1, Luis F. Rodr´ıguez2,3, Sac NictéX. Medina2, Laurent Loinard2, Josep M. Masqué2, Stan Kurtz2 and Keping Qiu4,5 1 Max-Planck-Institut für Radioastronomie, auf dem Hügel 69, 53121 Bonn, Germany 2 Centro de Radiostronom´ıay Astrof´ısica, Universidad Nacional Autónoma de México, 58089 Morelia, Mexico 3 Astronomy Department, Faculty of Science, King Abdulaziz University, PO Box 80203, 21589 Jeddah, Saudi Arabia 4 School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, 210093 Nanjing, PR China 5 Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093 Nan- jing, PR China E-mail contact: sdzib at mpifr-bonn.mpg.de Context: Recent high angular resolution radio observations of the ultracompact HII region W3(OH) confirm the presence of an extremely compact (0.′′ 05), time-variable source near its center. Aims: We use new, sensitive high angular resolution observations of radio continuum and recombination lines to study the compact source in W3(OH) and the ultracompact HII region itself. Methods: We reduced and analyzed extensive Jansky Very Large Array observations of W3(OH) in the continuum at 41.0 GHz and in the H54α and He54α lines. Results: Our images confirm there is the compact source and show that it is connected by a linear filament to the brightest part of W3(OH). We discuss several possible explanations for this structure and propose future observations that may clarify its nature. Accepted by Astronomy & Astrophysics Letters http://www.aanda.org/articles/aa/abs/2014/07/aa23855-14/aa23855-14.html

27 GW Ori: Inner disk readjustments in a triple system Min Fang1, Aurora Sicilia-Aguilar2,1, Veronica Roccatagliata3, David Fedele4, Thomas Henning5, Carlos Eiroa1 and AndréMüller6 1 Departamento de F´ısica Teórica, Universidad Autónoma de Madrid, Cantoblanco 28049, Madrid, Spain 2 SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK 3 Universitäts-Sternwarte München, Ludwig-Maximilians-Universität, Scheinerstr. 1, 81679, München, Germany 4 Max Planck Institut für Extraterrestrische Physik, Giessenbachstrasse 1, 85748, Garching, Germany 5 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany 6 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile E-mail contact: mfang.cn at gmail.com Context. Disks are expected to dissipate quickly in binary or multiple systems. Investigating such systems can improve our knowledge of the disk dispersal. The triple system GW Ori, still harboring a massive disk, is an excellent target. Aims. We study the young stellar system GW Ori, concentrating on its accretion/wind activity and disk properties. Methods. We use high-resolution optical spectra of GW Ori to do spectral classification and derive the radial velocities (RV). We analyze the wind and accretion activity using the emission lines in the spectra. We also use U-band photometry, which has been collected from the literature, to study the accretion variability of GW Ori. We characterize the disk properties of GW Ori by modeling its spectral energy distribution (SED). Results. By comparing our data to the synthetical spectra, we classify GW Ori as a G8 star. Based on the RVs derived from the optical spectra, we confirm the previous result as a close companion in GW Ori with a period of ∼242 days and an orbital semi-major axis of ∼1 AU. The RV residuals after the subtraction of the orbital solution with the equivalent widths of accretion-related emission lines vary with periods of 5–6.7 days during short time intervals, which are caused by the rotational modulation. The Hα and Hβ line profiles of GW Ori can be decomposed in two central-peaked emission components and one blue-shifted absorption component. The blue-shifted absorption components are due to a disk wind modulated by the orbital motion of the close companion. Therefore, the systems like GW Ori can be used to study the extent of disk winds. We find that the accretion rates of GW Ori are rather constant but can occasionally be enhanced by a factor of 2–3. We reproduce the SED of GW Ori by using disk models with gaps ∼25–55 AU in size. A small population of tiny dust particles within the gap produces the excess emission at near-infrared bands and the strong and sharp silicate feature at 10 µm. The SED of GW Ori exhibits dramatic changes on timescales of ∼20yr in the near-infrared bands, which can be explained as the change in the amount and distribution of small dust grains in the gap. We collect a sample of binary/multiple systems with disks in the literature and find a strong positive correlation between their gap sizes and separations from the primaries to companions, which is generally consistent with the prediction from the theory. Accepted by A&A http://arxiv.org/pdf/1407.4959

CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud M. Fernández-López1,2, H.G. Arce3, L. Looney1, L.G. Mundy4, S. Storm4, P.J. Teuben4, K. Lee4,1, D. Segura-Cox1, A. Isella5, J.J. Tobin6, E. Rosolowsky7,8, A. Plunkett3, W. Kwon9, J. Kauffmann5, E. Ostriker10, K. Tassis11,12, Y.L. Shirley13,14, M. Pound4 1 Department of Astronomy, University of Illinois at UrbanaChampaign, 1002 West Green Street, Urbana, IL 61801, USA 2 Current address: Instituto Argentino de Radioastronom´ıa, CCT-La Plata (CONICET), C.C.5, 1894, Villa Elisa, Argentina 3 Department of Astronomy,Yale University, P.O. Box 208101, New Haven, CT 06520-8101, USA 4 Department of Astronomy, University of Maryland, College Park, MD 20742, USA 5 Astronomy Department, California Institute of Technology, 1200 East California Blvd., Pasadena, CA 91125, USA 6 National Radio Astronomy Observatory, Charlottesville, VA 22903, USA 7 University of British Columbia, Okanagan Campus, Departments of Physics and Statistics, 3333 University Way, Kelowna BC V1V 1V7, Canada 8 University of Alberta, Department of Physics, 4-181 CCIS, Edmonton AB T6G 2E1, Canada

28 9 SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands 10 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA 11Department of Physics and Institute of Theoretical & Computational Physics, University of Crete, PO Box 2208, GR-710 03, Heraklion, Crete, Greece 12 Foundation for Research and Technology - Hellas, IESL, Voutes, 7110 Heraklion, Greece 13 Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA 14 Adjunct Astronomer, The National Radio Astronomy Observatory E-mail contact: manferna at gmail.com + We present the N2H (J = 1–0) map of the Serpens South molecular cloud obtained as part of the CARMA Large Area Star Formation Survey (CLASSy). The observations cover 250 square arcminutes and fully sample structures from 3000 AU to 3 pc with a velocity resolution of 0.16 km s−1, and they can be used to constrain the origin + and evolution of molecular cloud filaments. The spatial distribution of the N2H emission is characterized by long filaments that resemble those observed in the dust continuum emission by Herschel. However, the gas filaments are + typically narrower such that, in some cases, two or three quasi-parallel N2H filaments comprise a single observed dust continuum filament. The difference between the dust and gas filament widths casts doubt on Herschel ability to resolve the Serpens South filaments. Some molecular filaments show velocity gradients along their major axis, and two are characterized by a steep velocity gradient in the direction perpendicular to the filament axis. The observed velocity gradient along one of these filaments was previously postulated as evidence for mass infall toward the central cluster, but these kind of gradients can be interpreted as projection of large-scale turbulence. Accepted by ApJL http://arxiv.org/pdf/1407.0755

Distributed Low-Mass Star Formation in the IRDC G34.43+00.24 Jonathan B. Foster1, Hctor G. Arce2, Marc Kassis3, Patricio Sanhueza4, Jame M. Jackson4, Susanna C. Finn5, Stella Offner2, Takeshi Sakai6, Nami Sakai7, Satoshi Yamamoto7, Andrs E. Guzmn8 and Jill M. Rathborne9 1 Yale Center for Astronomy and Astrophysics, New Haven, CT 06520, USA 2 Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520, USA 3 W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Kamuela, HI 96743, USA 4 Institute for Astrophysical Research, Boston University, Boston, MA 02215, USA 5 Center for Atmospheric Research, UMASS Lowell, 600 Suffolk St., Lowell MA 01854, USA 6 Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo 182- 8585, Japan 7 Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan 8 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 9 CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710, Australia E-mail contact: jonathan.b.foster at yale.edu We have used deep near-infrared observations with adaptive optics to discover a distributed population of low-mass protostars within the filamentary Infrared Dark Cloud G34.43+00.24. We use maps of dust emission at multiple wavelengths to determine the column density structure of the cloud. In combination with an empirically-verified model of the magnitude distribution of background stars, this column density map allows us to reliably determine overdensities of red sources that are due to embedded protostars in the cloud. We also identify protostars through their extended emission in K-band which comes from excited H2 in protostellar outflows or reflection nebulosity. We find a population of distributed low-mass protostars, suggesting that low-mass protostars may form earlier than, or contemporaneously with, high-mass protostars in such a filament. The low-mass protostellar population may also produce the narrow linewidth SiO emission observed in some clouds without high-mass protostars. Finally, we use a molecular line map of the cloud to determine the virial parameter per unit length along the filament and find that the highest mass protostars form in the most bound portion of the filament, as suggested by theoretical models. Accepted by ApJ http://arxiv.org/pdf/1407.6003

29 A Dynamically Collapsing Core and a Precursor of a Core in a Filament Supported by Turbulent and Magnetic Pressures Ray S. Furuya1, Yoshimi Kitamura2 and Hiroko Shinnaga3 1 Center for General Education, the University of Tokushima, Minami Jousanjima-Machi 1-1, Tokushima, Tokushima 770-8502, Japan 2 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa 229-8510, Japan 3 Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan E-mail contact: rsf at tokushima-u.ac.jp To study physical properties of the natal filament gas around the cloud core harboring an exceptionally young low- mass protostar GF9-2, we carried out J = 1 − 0 line observations of 12CO, 13CO, and C18O molecules using the Nobeyama 45m telescope. The mapping area covers ∼ 1/5 of the whole filament. Our tCO and CeO maps clearly demonstrate that the core formed at the local density maxima of the filament, and the internal motions of the filament gas are totally governed by turbulence with Mach number of ∼2. We estimated the scale height of the filament to −3 be H = 0.3 ∼ 0.7 pc, yielding the central density of nc = 700 ∼ 4200 cm . Our analysis adopting an isothermal cylinder model shows that the filament is supported by the turbulent and magnetic pressures against the radial and axial collapse due to self-gravity. Since both the dissipation time scales of the turbulence and the transverse magnetic fields can be comparable to the free-fall time of the filament gas of 106 years, we conclude that the local decay of the supersonic turbulence made the filament gas locally unstable, hence making the core collapse. Furthermore, we newly detected a gas condensation with velocity width enhancement to ∼0.3 pc south-west of the GF9-2 core. The condensation has a radius of ∼0.15pc and an LTE mass of ∼5 M⊙. Its internal motion is turbulent with Mach number of ∼3, suggestive of a gravitationally unbound state. Considering the uncertainties in our estimates, however, we propose that the condensation is a precursor of a cloud core which would have been produced by the collision of the two gas components identified in the filament. Accepted by ApJ http://arxiv.org/pdf/1407.4857

SIMP J2154−1055: A New Low-Gravity L4β Brown Dwarf Candidate Member of the Argus Association Jonathan Gagné1, David Lafreniére1, RenéDoyon1, Etienne´ Artigau1, Lison Malo1,2, Jasmin Robert1, and Daniel Nadeau1 1 Département de Physique, Universitéde Montréal, C.P. 6128 Succ. Centre-ville, Montréal, QC H3C 3J7, Canada 2 Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743, USA E-mail contact: charlene.lefevre at obspm.fr We present SIMP J21543454−1055308, a new L4β brown dwarf identified in the Sondage Infrarouge de Mouvement Propre (SIMP) survey that displays signs of low gravity in its near-infrared spectrum. Using the Bayesian Analysis for Nearby Young AssociatioNs II (BANYAN II), we show that it is a candidate member of the Argus association, albeit with a 21% probability that it is a contaminant from the field. Measurements of radial velocity and parallax will be needed to verify its membership. If it is a member of Argus (age 30–50 Myr), then this object would have a planetary mass of 10 ± 0.5 MJup. Accepted by ApJL http://arxiv.org/pdf/1407.5344

A spectroscopic census in young stellar regions: the sigma Orionis cluster Jesús Hernández1, Nuria Calvet2, Alice Perez1,3, Cesar Briceño4, Lorenzo Olguin5, Maria E. Contreras6, Lee Hartmann2, Lori Allen7, Catherine Espaillat8 and Hernan Ram´ırez1 1 Centro de Investigaciones de Astronom´ıa, Apdo. Postal 264, Mérida 5101-A, Venezuela 2 Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109, US

30 3 Departamento de F´ısica, Universidad de Oriente, Venezuela 4 Cerro Tololo Interamerican Observatory, Casilla 603, La Serena, Chile 5 Depto. de Investigación en F´ısica, Universidad de Sonora, Sonora, México 6 Instituto de Astronom´ıa, Universidad Nacional Autónoma de México, Ensenada, BC, México 7 National Optical Astronomy Observatory, 950 North Cherry A venue, Tucson, AZ 85719, USA 8 Department of Astronomy, Boston University, 725 Commonwea lth Avenua, Boston, MA 02215, USA E-mail contact: hernandj at cida.gob.ve We present a spectroscopic survey of the stellar population of the σ Orionis cluster. We have obtained spectral types for 340 stars. Spectroscopic data for spectral typing come from several spectrographs with similar spectroscopic coverage and resolution. More than a half of stars of our sample are members confirmed by the presence of lithium in absorption, strong Hα in emission or weak gravity-sensitive features. In addition, we have obtained high resolution (R∼34000) spectra in the Hα region for 169 stars in the region. Radial velocities were calculated from this data set. The radial velocity distribution for members of the cluster is in agreement with previous work. Analysis of the profile of the Hα line and infrared observations reveals two binary systems or fast rotators that mimic the Hα width expected in stars with accretion disks. On the other hand there are stars with optically thick disks and narrow Hα profile not expected in stars with accretion disks. This contribution constitutes the largest homogeneous spectroscopic data set of the σ Orionis cluster to date. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1408.0225

VERA and ALMA Observations of the H2O Supermaser Burst in Orion KL Tomoya Hirota1,2, Masato Tsuboi3, Yasutaka Kurono4,5, Kenta Fujisawa6,7, Mareki Honma1,2, Mi Ky- oung Kim8, Hiroshi Imai9 and Yoshinori Yonekura10 1 National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan 2 Department of Astronomical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588, Japan 3 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 229- 8510, Japan 4 Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan 5 Joint ALMA Observatory, Alonso de Cordova 3107 Vitacura, Santiago 763-0355, Chile 6 Department of Physics, Faculty of Science, Yamaguchi University, Yamaguchi, Yamaguchi 753-8512, Japan 7 The Research Institute of Time Studies, Yamaguchi University, Yamaguchi, Yamaguchi 753-8511, Japan 8 Korea Astronomy and Space Science Institute, Hwaam-dong 61-1, Yuseong-gu, Daejeon, 305-348, Republic of Korea 9 Graduate School of Science and Engineering, Kagoshima University, Kagoshima, Kagoshima 890-0065, Japan 10 Center for Astronomy, Ibaraki University, Mito, Ibaraki 310-8512, Japan E-mail contact: tomoya.hirota at nao.ac.jp

The 22 GHz H2O maser in Orion KL has shown extraordinary burst events in 1979-1985 and 1998-1999, sometimes called supermaser. We have conducted monitoring observations of the supermaser in Orion KL using VERA, VLBI Exploration of Radio Astrometry, in the current third burst since 2011 March. Three flux maxima are detected in 2011 and 2012 with rising and falling timescales of 2-7 months. Time variations of the supermaser seem symmetric for all of the active phases. The maximum total flux density of 135000 Jy is observed in 2012 June while it is still one order of magnitude lower than those in previous bursts. The supermaser consists of two spatially different components at different velocities. They are elongated along a northwest-southeast direction perpendicular to the low-velocity outflow driven by Source I. Proper motions of the supermaser features with respect to Source I are measured toward west and southwest directions, almost parallel to the low-velocity outflow. The flux density and linewidth show an anti-correlation as expected for an unsaturated maser emission. The supermaser is located close to the methylformate (HCOOCH3) line and continuum emission peaks in the Orion Compact Ridge detected by ALMA, Atacama Large Millimeter/Submillimeter Array. The broader velocity range of the weak HCOOCH3 emission at the supermaser position would be an evidence of a shock front. On the other hand, the 321 GHz H2O line is not detected at the position of the supermaser. It can be explained qualitatively by one of the theoretical H2O excitation models without extraordinary conditions. Our results support a scenario that the supermaser is excited in the dense gas interacting

31 with the low-velocity outflow in the Compact Ridge. The extremely high flux density and its symmetric time variation for rising and falling phases could be explained by a beaming effect during the amplification process rather than changes in physical conditions. Accepted by PASJ http://arxiv.org/pdf/1407.2757

The Census of Complex Organic Molecules in the Solar-type Protostar IRAS16293-2422 Ali A. Jaber1,2,3, C. Ceccarelli1,2, C. Kahane1,2 and E. Caux4 1 Universite Grenoble Alpes, IPAG, F-38000 Grenoble, France 2 CNRS, IPAG, F-38000 Grenoble, France 3 University of AL-Muthana, AL-Muthana, Iraq 4 Universite de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse, France E-mail contact: ali.al-edhari at obs.ujf-grenoble.fr Complex Organic Molecules (COMs) are considered crucial molecules, since they are connected with organic chemistry, at the basis of the terrestrial life. More pragmatically, they are molecules in principle difficult to synthetize in the harsh interstellar environments and, therefore, a crucial test for astrochemical models. Current models assume that several COMs are synthesised on the lukewarm grain surfaces (∼>30–40 K), and released in the gas phase at dust > < temperatures ∼100 K. However, recent detections of COMs in ∼20 K gas demonstrate that we still need important pieces to complete the puzzle of the COMs formation. We present here a complete census of the oxygen and nitrogen bearing COMs, previously detected in different ISM regions, towards the solar type protostar IRAS16293-2422. The census was obtained from the millimeter-submillimeter unbiased spectral survey TIMASSS. Six COMs, out of the 29 searched for, were detected: methyl cyanide, ketene, acetaldehyde, formamide, dimethyl ether, and methyl formate. The multifrequency analysis of the last five COMs provides clear evidence that they are present in the cold (∼<30 K) envelope of IRAS16293-2422, with abundances 0.03–2 ×10−10. Our data do not allow to support the hypothesis that the COMs abundance increases with increasing dust temperature in the cold envelope, as expected if COMs were predominately formed on the lukewarm grain surfaces. Finally, when considering also other ISM sources, we find a strong correlation over five orders of magnitude, between the methyl formate and dimethyl ether and methyl formate and formamide abundances, which may point to a link between these two couples of species, in cold and warm gas. Accepted by The Astrophysical Journal arxiv:1406.7195

Misaligned protoplanetary disks in a young binary star system Eric L. N. Jensen1 and Rachel Akeson2 1 Dept. of Physics and Astronomy, Swarthmore College, 500 College Avenue, Swarthmore, Pennsylvania 19081, USA 2 NASA Exoplanet Science Institute, IPAC/Caltech, Pasadena, California 91125, USA E-mail contact: ejensen1 at swarthmore.edu Many extrasolar planets follow orbits that differ from the nearly coplanar and circular orbits found in our Solar System; their orbits may be eccentric or inclined with respect to the host star’s equator, and the population of giant planets orbiting close to their host stars suggests appreciable orbital migration. There is at present no consensus on what produces such orbits. Theoretical explanations often invoke interactions with a binary companion star in an orbit that is inclined relative to the planet’s orbital plane. Such mechanisms require significant mutual inclinations between the planetary and binary star orbital planes. The protoplanetary disks in a few young binaries are misaligned, but often the measurements of these misalignments are sensitive only to a small portion of the inner disk, and the three-dimensional misalignment of the bulk of the planet-forming disk mass has hitherto not been determined. Here we report that the protoplanetary disks in the young binary system HK Tauri are misaligned by 60◦ to 68◦, such that one or both of the disks are significantly inclined to the binary orbital plane. Our results demonstrate that the necessary conditions exist for misalignment-driven mechanisms to modify planetary orbits, and that these conditions are present at the time of planet formation, apparently because of the binary formation process.

32 Accepted by Nature (511:567 - July 31, 2014) http://www.nature.com/nature/journal/v511/n7511/full/nature13521.html http://arxiv.org/pdf/1407.8211

Effect of dust grain porosity on the appearance of protoplanetary disks F. Kirchschlager1 and S. Wolf1 1 Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24098 Kiel, Germany E-mail contact: kirchschlager at astrophysik.uni-kiel.de We theoretically analyze protoplanetary disks consisting of porous dust grains. In the analysis of observations of protoplanetary disks the dust phase is often assumed to consist of spherical grains, allowing one to apply the Mie scattering formalism. However, in reality, the shape of dust grains is expected to deviate strongly from that of a sphere. We investigate the influence of porous dust grains on the temperature distribution and observable appearance of protoplanetary disks for dust grain porosities of up to 60%. We performed radiative transfer modeling to simulate the temperature distribution, spectral energy distribution, and spatially resolved intensity and polarization maps. The optical properties of porous grains were calculated using the method of discrete dipole approximation. We find that the flux in the optical wavelength range is for porous grains higher than for compact, spherical grains. The profile of the silicate peak at 9.7 µm strongly depends on the degree of grain porosity. The temperature distribution shows significant changes in the direction perpendicular to the midplane. Moreover, simulated polarization maps reveal an increase of the polarization degree by a factor of about four when porous grains are considered, regardless of the disk inclination. The polarization direction is reversed in selected disk regions, depending on the wavelength, grain porosity, and disk inclination. We discuss several possible explanations of this effect and find that multiple scattering explains the effect best. Porosity influences the observable appearance of protoplanetary disks. In particular, the polarization reversal shows a dependence on grain porosity. The physical conditions within the disk are altered by porosity, which might have an effect on the processes of grain growth and disk evolution. Accepted by A&A http://arxiv.org/pdf/1407.6575

A Classiﬁcation Scheme for Young Stellar Objects Using the WIDE-FIELD INFRARED SURVEY EXPLORER AllWISE Catalog: Revealing Low-Density Star Formation in the Outer Galaxy Xavier P. Koenig1 and David T. Leisawitz2 1 Department of Astronomy, Yale University, New Haven, CT 06520, USA 2 NASA Goddard Space Flight Center, Code 605, Greenbelt, MD 20771, USA E-mail contact: xavier.koenig at yale.edu We present an assessment of the performance of WISE and the AllWISE data release in a section of the Galactic Plane. We lay out an approach to increasing the reliability of point source photometry extracted from the AllWISE catalog in Galactic Plane regions using parameters provided in the catalog. We use the resulting catalog to construct a new, revised young star detection and classiﬁcation scheme combining WISE and 2MASS near and mid-infrared colors and magnitudes and test it in a section of the Outer Milky Way. The clustering properties of the candidate Class I and II stars using a nearest neighbor density calculation and the two-point correlation function suggest that the majority of stars do form in massive star forming regions, and any isolated mode of star formation is at most a small fraction of the total star forming output of the Galaxy. We also show that the isolated component may be very small and could represent the tail end of a single mechanism of star formation in line with models of molecular cloud collapse with supersonic turbulence and not a separate mode all to itself. Accepted by ApJ http://arxiv.org/pdf/1407.2262

33 Herschel Key Program, “Dust, Ice, and Gas In Time” (DIGIT): the origin of molecular and atomic emission in low-mass protostars in Taurus Jeong-Eun Lee1,3, Jinhee Lee2, Seokho Lee1, Neal J. Evans II3, Joel D. Green3 1 Department of Astronomy and Space Science, Kyung Hee University, Yongin-shi, Kyungki-do 449-701, Korea 2 Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602-2451, USA 3 Department of Astronomy, Univ. of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205, USA E-mail contact: jeongeun.lee at khu.ac.kr Six low-mass embedded sources (L1489, L1551-IRS5, TMR1, TMC1-A, L1527, and TMC1) in Taurus have been observed with Herschel-PACS to cover the full spectrum from 50 to 210 µm as part of the Herschel key program, “Dust, Ice, and Gas In Time (DIGIT)”. The relatively low intensity of the interstellar radiation field surrounding Taurus minimizes contamination of the [C II] emission associated with the sources by diffuse emission from the cloud surface, allowing study of the [C II] emission from the source. In several sources, the [C II] emission is distributed along the outflow, as is the [O I] emission. The atomic line luminosities correlate well with each other, as do the molecular lines, but the atomic and molecular lines correlate poorly. The relative contribution of CO to the total gas cooling is constant at ∼30%, while the cooling fraction by H2O varies from source to source, suggesting different shock properties resulting in different photodissociation levels of H2O. The gas with a power-law temperature distribution with a moderately high density can reproduce the observed CO fluxes, indicative of CO close to LTE. However, H2O is mostly subthermally excited. L1551-IRS5 is the most luminous source (Lbol = 24.5 L⊙) and the [O I] 63.1 µm line accounts for more than 70% of its FIR line luminosity, suggesting complete photodissociation of H2O by a J-shock. In L1551-IRS5, the central velocity shifts of the [O I] line, which exceed the wavelength calibration uncertainty (∼70 km s−1) of PACS, are consistent with the known red- and blue-shifted outflow direction. Accepted by ApJS http://arxiv.org/pdf/1407.3033

Dust properties inside molecular clouds from coreshine modeling and observations C. Lefévre1, L. Pagani1, M. Juvela2, R. Paladini3, R. Lallement4, D.J. Marshall5, M. Andersen6,7, A. Bacmann6,7, P. M. McGehee3, L. Montier8,9, A. Noriega-Crespo3,10, V.-M. Pelkonen2,11, I. Ristorcelli8,9, and J. Steinacker6,7 1 LERMA & UMR8112 du CNRS, Observatoire de Paris, 61, Av. de l’Observatoire, 75014 Paris, France 2 Department of Physics, P.O.Box 64, FI-00014, University of Helsinki, Finland 3 Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA 4 GEPI Observatoire de Paris, CNRS, UniversitéParis Diderot, Place Jules Janssen 92190 Meudon, France 5 Laboratoire d’astrophysique Instrumentation Modelisation (AIM) Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France 6 UniversitéGrenoble Alpes, IPAG, F-38000 Grenoble, France 7 CNRS, IPAG, F-38000 Grenoble, France 8 Universitéde Toulouse, UPS-OMP, IRAP, 31028 Toulouse Cedex 4, France 9 CNRS, IRAP, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France 10 Space Telescope Science Institute, Baltimore, MD, 21218, USA 11 Finnish Centre for astronomy with ESO, University of Turku, Väisäläntie 20, FI-21500 PIIKKI O, Finland E-mail contact: charlene.lefevre at obspm.fr Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 µm that dominates absorption, has revealed its ability to explore the densest parts of clouds. We want to use this effect to constrain the dust parameters. The goal is to investigate to what extent grain growth (at constant dust mass) inside molecular clouds is able to explain the coreshine observations. We aim to find dust models that can explain a sample of Spitzer coreshine data. We also look at the consistency with near-infrared data we obtained for a few clouds. Methods. We selected four regions with a very high occurrence of coreshine cases: Taurus-Perseus, Cepheus, Chameleon and L183/L134. We built a grid of dust models and investigated the key parameters to reproduce the general trend

34 of surface brightnesses and intensity ratios of both coreshine and near-infrared observations with the help of a 3D Monte-Carlo radiative transfer code. The grid parameters allow to investigate the effect of coagulation upon spherical grains up to 5 µm in size derived from the DustEm diffuse interstellar medium grains. Fluffiness (porosity or fractal degree), ices, and a handful of classical grain size distributions were also tested. We used the near- and mostly mid- infrared intensity ratios as strong discriminants between dust models. Results. The determination of the background field intensity at each wavelength is a key issue. In particular, an especially strong background field explains why we do not see coreshine in the Galactic plane at 3.6 and 4.5 µm. For starless cores, where detected, the observed 4.5 µm / 3.6 µm coreshine intensity ratio is always lower than ∼0.5 which is also what we find in the models for the Taurus-Perseus and L183 directions. Embedded sources can lead to higher fluxes (up to four times greater than the strongest starless core fluxes) and higher coreshine ratios (from 0.5 to 1.1 in our selected sample). Normal interstellar radiation field conditions are sufficient to find suitable grain models at all wavelengths for starless cores. The standard interstellar grains are not able to reproduce observations and, due to the multi-wavelength approach, only a few grain types meet the criteria set by the data. Porosity does not affect the flux ratios while the fractal dimension helps to explain coreshine ratios but does not seem able to reproduce near-infrared observations without a mix of other grain types. Conclusions. Combined near- and mid-infrared wavelengths confirm the potential to reveal the nature and size distribution of dust grains. Careful assessment of the environmental parameters (interstellar and background fields, embedded or nearby reddened sources) is required to validate this new diagnostic. Accepted by A&A http://arxiv.org/pdf/1407.5804

Unbiased water and methanol maser surveys of NGC 1333 A-Ran Lyo1, Jongsoo Kim1, Do-Young Byun1, and Ho-Gyu Lee1 1 Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro Yuseong-gu, Daejeon 305-348, Republic of Korea E-mail contact: arl at kasi.re.kr

We present the results of unbiased 22 GHz H2O water and 44 GHz class I CH3OH methanol maser surveys in the central 7′ × 10′ area of NGC 1333 and two additional mapping observations of a 22 GHz water maser in a ∼3′ × 3′ area of the IRAS4A region. In the 22 GHz water maser survey of NGC 1333 with sensitivity of σ ∼ 0.3 Jy, we ′′ confirmed masers toward H2O(B) in the region of HH 7–11 and IRAS4B. We also detected new water masers at ∼20 away in the western direction of IRAS4B or ∼25′′ away in the southern direction of IRAS4A. We could not however find young stellar objects or molecular outflows associated with them. They showed two different velocity components of ∼0 and ∼16 km s−1, which are blue- and red-shifted relative to the adopted systemic velocity of ∼7 km s−1 for NGC 1333. They also showed time variabilities in both intensity and velocity from multi-epoch observations and an anti-correlation between the intensities of the blue- and the red-shifted velocity components. We suggest that the unidentified powering source of these masers might be in the earliest evolutionary stage of star formation before the onset of molecular outflows. Finding this kind of water masers is only possible by an unbiased blind survey. In the 44 GHz methanol maser survey with sensitivity of σ ∼ 0.5 Jy, we confirmed masers toward the IRAS4A2 and the eastern shock region of the IRAS2A. Both sources are also detected in 95 and 132 GHz methanol maser lines. In addition, we had new detections of methanol masers at 95 and 132 GHz toward IRAS4B. In terms of the isotropic luminosity, we detected the methanol maser sources brighter than ∼5 × 1025 erg s−1 from our unbiased survey. Accepted by AJ http://arxiv.org/pdf/1407.6776

NGC 7538 : Multiwavelength Study of Stellar Cluster Regions associated with IRS 1–3 and IRS 9 sources K. K. Mallick1, D. K. Ojha1, M. Tamura2, A. K. Pandey3, S. Dib4,5, S. K. Ghosh1,6, K. Sunada7, I. Zinchenko8,9, L. Pirogov8,9 and M. Tsujimoto10 1 Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India

35 2 National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan 3 Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 129, India 4 Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen, Denmark 5 Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5-7., DK-1350, Copenhagen, Denmark 6 National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007, India 7 Mizusawa VLBI Observatory, NAOJ, 2-12 Hoshi-ga-oka, Mizusawa-ku, Oshu-shi, Iwate 023-0861, Japan 8 Institute of Applied Physics, Russian Academy of Sciences, 46 Uljanov str., Nizhny Novgorod 603950, Russia 9 Lobachevsky State University of Nizhni Novgorod, 23 Prospekt Gagarina, 603950, Nizhni Novgorod, Russia 10 Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan E-mail contact: kshitiz at tifr.res.in We present deep and high-resolution (FWHM ∼ 0.4 arcsec) near-infrared (NIR) imaging observations of the NGC 7538 IRS 1–3 region (in JHK bands), and IRS 9 region (in HK bands) using the 8.2 m Subaru telescope. The NIR analysis is complemented with GMRT low-frequency observations at 325, 610, and 1280 MHz, molecular line observations of H13CO+ (J=1–0), and archival Chandra X-ray observations. Using the ‘J − H/H − K’ diagram, 144 ClassII and 24 Class I young stellar object (YSO) candidates are identiﬁed in the IRS 1–3 region. Further analysis using ‘K/H − K’ diagram yields 145 and 96 red sources in the IRS 1-3 and IRS 9 regions, respectively. A total of 27 sources are found to have X-ray counterparts. The YSO mass function (MF), constructed using a theoretical mass-luminosity relation, shows peaks at substellar (∼0.08–0.18 M⊙ ) and intermediate (∼1–1.78 M⊙ ) mass ranges for the IRS1–3 region. The MF can be ﬁtted by a power law in the low mass regime with a slope of Γ ∼ 0.54-0.75, which is much shallower than the Salpeter value of 1.35. An upper limit of 10.2 is obtained for the star to brown dwarf ratio in the IRS 1–3 region. GMRT maps show a compact H ii region associated with the IRS1–3 sources, whose spectral index of 0.87 ± 0.11 suggests optical thickness. This compact region is resolved into three separate peaks in higher resolution 1280MHz map, and the ‘East’ sub-peak coincides with the IRS 2 source. H13CO+ (J=1–0) emission reveals peaks in both IRS 1–3 and IRS 9 regions, none of which are coincident with visible nebular emission, suggesting the presence of dense cloud nearby. The virial masses are approximately of the order of 1000 M⊙ and 500 M⊙ for the clumps in IRS 1–3 and IRS 9 regions, respectively. Accepted by MNRAS http://arxiv.org/pdf/1407.1987

Impact of planet–planet scattering on the formation and survival of debris disks F. Marzari1 1 Dept. of Physics, University of Padova, 35131 Italy E-mail contact: marzari at pd.infn.it Planet–planet scattering is a major dynamical mechanism able to significantly alter the architecture of a planetary system. In addition to that, it may also affect the formation and retention of a debris disk by the system. A violent chaotic evolution of the planets can easily clear leftover planetesimal belts preventing the ignition of a substantial collisional cascade that can give origin to a debris disk. On the other end, a mild evolution with limited steps in eccentricity and semimajor axis can trigger the formation of a debris disk by stirring an initially quiet planetesimal belt. The variety of possible effects that planet–planet scattering can have on the formation of debris disks is analysed and the statistical probability of the different outcomes is evaluated. This leads to the prediction that systems which underwent an episode of chaotic evolution might have a lower probability of harboring a debris disk. Accepted by MNRAS http://arxiv.org/pdf/1407.8018

New constraints on the dust surrounding HR 4796 A J. Milli1,2, D. Mawet2, C. Pinte3,1, A.-M. Lagrange1, D. Mouillet1, J.H. Girard2, J.-C. Augereau1, J. De Boer2, L. Pueyo4, and E.´ Choquet4

36 1 UniversitéGrenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble, France 2 European Southern Observatory (ESO), Alonso de Crdova 3107, Vitacura, Casilla 19001, Santiago, Chile 3 UMI-FCA, CNRS/INSU France (UMI 3386), and Departamento de Astronoma, Universidad de Chile, Casilla 36-D Santiago, Chile 4 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD 21218, USA E-mail contact: julien.milli at obs.ujf-grenoble.fr HR 4796 A is surrounded by a well-structured and very bright circumstellar disc shaped as an annulus with many interesting features: very sharp inner and outer edges, brightness asymmetries, center offset and suspected distortions in the ring. We aim to constrain the properties of the dust surrounding the star HR 4796A, in particular the grain size and composition. We also want to confirm and refine the morphological parameters derived from previous scattered light observations, and reveal the dust spatial extent in regions unexplored so far due to their proximity to the star. We have obtained new images in polarized light of the binary system HR 4796A and B in the Ks and L′ band with the NaCo instrument at the Very Large Telescope (VLT). In addition, we revisit two archival data obtained in the L′ band with that same instrument and at 2.2 µm with the NICMOS instrument on the Hubble Space Telescope. We complement these observations with simulations using the radiative transfer code MCFOST to investigate the dust properties. We explore a grid of models with various dust composition and sizes. We detect the disc in polarized light in the Ks band and reveal for the first time the innermost regions down to 0′′. 3 along the minor axis. We measure a polarized fraction of 29%±8% in the two disc ansae, with a maximum occurring more than 13◦ westwards from the ansae. A very pronounced brightness asymmetry between the North-West and South-East side is detected. This contradicts the asymmetry previously reported in all images of the disc in unpolarized light at wavelengths smaller than or equal to 2.2 µm and is inconsistent with the predicted scattered light from spherical grains using the Mie theory. Accepted by A&A http://arxiv.org/pdf/1407.2539

Cluster Formation Triggered by Filament Collisions in Serpens South Fumitaka Nakamura1,2,3,4, Koji Sugitani5, Tomohiro Tanaka6, Hiroyuki Nishitani2, Kazuhito Dobashi7, Tomomi Shimoikura7, Yoshito Shimajiri8, Ryohei Kawabe1, Yoshinori Yonekura9, Izumi Mizuno2,11, Kimihiko Kimura6, Kazuki Tokuda6, Minato Kozu6, Nozomi Okada6, Yutaka Hasegawa6, Hideo Ogawa6, Seiji Kameno12, Hiroko Shinnaga1, Munetake Momose13, Taku Nakajima14, Toshikazu Onishi6, Hiroyuki Maezawa6, Tomoya Hirota1, Shuro Takano2,3, Daisuke Iono1, Nario Kuno2,3,15, Satoshi Yamamoto16 1 National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan 2 Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1305, Japan 3 The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan 4 Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106-4030 5 Graduate School of Natural Sciences, Nagoya City University, Mizuho-ku, Nagoya 467-8501, Japan 6 Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, Sakai, Osaka 599-8531, Japan 7 Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan 8 Laboratoire AIM, CEA/DSM-CNRS-Universit´eParis Diderot, IRFU/Service dAstrophysique,´ CEA Saclay, F-91191 Gif-sur-Yvette, France 9 Center for Astronomy, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan 10 Institute of Astrophysics and Planetary Sciences, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512, Japan 11 Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890- 0065, Japan 12 Joint ALMA Observatory, Alonso de Crdova 3107 Vitacura, Santiago, Chile 13 Institute of Astrophysics and Planetary Sciences, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512, Japan 14 Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan 15 Department of Physics, Graduate School of Pure and Applied Sciences, The University of Tsukuba, 1-1-1 Tennodai, Tsukuba Ibaraki 305-8577, Japan 16 Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan

37 E-mail contact: fumitaka.nakamura at nao.ac.jp The Serpens South infrared dark cloud consists of several filamentary ridges, some of which fragment into dense + clumps. On the basis of CCS (JN = 43–32), HC3N (J = 5–4), N2H (J = 1–0), and SiO (J = 2–1, v = 0) observations, we investigated the kinematics and chemical evolution of these filamentary ridges. We find that CCS is extremely abundant along the main filament in the protocluster clump. We emphasize that Serpens South is the + first cluster-forming region where extremely-strong CCS emission is detected. The CCS-to-N2H abundance ratio is estimated to be about 0.5 toward the protocluster clump, whereas it is about 3 in the other parts of the main filament. We identify six dense ridges with different VLSR. These ridges appear to converge toward the protocluster clump, suggesting that the collisions of these ridges may have triggered cluster formation. The collisions presumably happened within a few × 105 yr because CCS is abundant only in such a short time. The short lifetime agrees with the fact that the number fraction of Class I objects, whose typical lifetime is 0.4 × 105 yr, is extremely high as about 70 percent in the protocluster clump. In the northern part, two ridges appear to have partially collided, forming a V-shape clump. In addition, we detected strong bipolar SiO emission that is due to the molecular outflow blowing out of the protostellar clump, as well as extended weak SiO emission that may originate from the filament collisions. Accepted by ApJL http://arxiv.org/pdf/1407.1235

Proper Motions of Young Stellar Outflows in the Mid-Infrared with Spitzer. II. HH 377/Cep E A. Noriega-Crespo1,3, A.C. Raga2, A. Moro-Mart´ın3, N. Flagey4,6, and S.J. Carey5 1 Infrared Processing and Analysis Center, California Institute of Technology, CA, 91125, USA 2 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ap. 70-543, 04510 D.F., México 3 Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD, 21218, USA 4 Jet Propulsion Laboratory, California Institute of Technology, CA, 91099, USA 5 Spitzer Science Center, California Institute of Technology, CA, 91125, USA 6 Institute for Astronomy, 640 North Aóhoku Place, Hilo, HI, 96720, USA E-mail contact: anoriega at stsci.edu We have used multiple mid-infrared observations at 4.5 µm obtained with the Infrared Array Camera, of the compact (∼1.4′) young stellar bipolar outflow Cep E to measure the proper motion of its brightest condensations. The images span a period of ∼6 yr and have been reprocessed to achieve a higher angular resolution (∼0.′′8) than their normal beam (2′′). We found that for a distance of 730 pc, the tangential velocities of the North and South outflow lobes are 62±29 and 94±6 km s−1 respectively, and moving away from the central source roughly along the major axis of the flow. A simple 3D hydrodynamical simulation of the H2 gas in a precessing outflow supports this idea. Observations and model confirm that the molecular Hydrogen gas, traced by the pure rotational transitions, moves at highly supersonic velocities without being dissociated. This suggests either a very efficient mechanism to reform H2 molecules along these shocks or the presence of some other mechanism (e.g. strong magnetic field) that shields the H2 gas. Accepted by New Journal of Physics http://arxiv.org/pdf/1407.6009

Water Delivery and Giant Impacts in the ‘Grand Tack’ Scenario David P. O’Brien1, Kevin J. Walsh2, Alessandro Morbidelli3, Sean N. Raymond4,5, and Avi M. Mandell6 1 Planetary Science Institute, 1700 E. Ft. Lowell, Suite 106, Tucson, AZ 85719, USA 2 Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300 Boulder, Colorado 80302, USA 3 Universitéde Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur BP 4229, 06304 Nice Cedex 4, France 4 Universitéde Bordeaux, Observatoire Aquitain des Sciences de l’Univers, 2 Rue de l’Observatoire BP 89, F-33270 Floirac Cedex, France 5 CNRS, UMR 5804, Laboratoire d’Astrophysique de Bordeaux, 2 Rue de l’Observatoire BP 89, F-33270 Floirac

38 Cedex, France 6 NASA Goddard Space Flight Center, Code 693, Greenbelt, MD 20771, USA E-mail contact: obrien at psi.edu A new model for terrestrial planet formation (Hansen 2009, Walsh et al. 2011) has explored accretion in a truncated protoplanetary disk, and found that such a configuration is able to reproduce the distribution of mass among the planets in the Solar System, especially the Earth/Mars mass ratio, which earlier simulations have generally not been able to match. Walsh et al. tested a possible mechanism to truncate the disk–a two-stage, inward-then-outward migration of Jupiter and Saturn, as found in numerous hydrodynamical simulations of giant planet formation. In addition to truncating the disk and producing a more realistic Earth/Mars mass ratio, the migration of the giant planets also populates the asteroid belt with two distinct populations of bodies–the inner belt is filled by bodies originating inside of 3 AU, and the outer belt is filled with bodies originating from between and beyond the giant planets (which are hereafter referred to as ‘primitive’ bodies). We find here that the planets will accrete on order 1–2% of their total mass from primitive planetesimals scattered onto planet-crossing orbits during the formation of the planets. For an assumed value of 10% for the water mass fraction of the primitive planetesimals, this model delivers a total amount of water comparable to that estimated to be on the Earth today. While the radial distribution of the planetary masses and the dynamical excitation of their orbits are a good match to the observed system, we find that the last giant impact is typically earlier than 20 Myr, and a substantial amount of mass is accreted after that event. However, 5 of the 27 planets larger than half an Earth mass formed in all simulations do experience large late impacts and subsequent accretion consistent with the dating of the Moon-forming impact and the estimated amount of mass accreted by Earth following that event. Accepted by Icarus http://arxiv.org/pdf/1407.3290

Imaging the Inner and Outer Gaps of the Pre-Transitional Disk of HD 169142 at 7 mm Mayra Osorio1, Guillem Anglada1, Carlos Carrasco-González2, JoséM. Torrelles3, Enrique Mac´ıas1, Luis F. Rodr´ıguez2, JoséF. Gómez1, Paola D’Alessio2, Nuria Calvet4, Erick Nagel5, William R. F.6, Sascha P. Quanz7, Maddalena Reggiani7 and Juan M. Mayen-Gijon1 1 Instituto de Astrof´ısica de Andaluc´ıa(CSIC), Glorieta de la Astronom´ıas/n, E-18008 Granada, Spain 2 Centro de Radioastronom´ıay Astrof´ısica UNAM, Apartado Postal 3-72 (Xangari), 58089 Morelia, Michoacán, Mexico 3 Institut de Ciències de l’Espai (CSIC)-Institut de Ciències del Cosmos (UB)/IEEC, Mart´ıi Franquès 1, E-08028 Barcelona, Spain 4 Department of Astronomy, University of Michigan, 825 Dennison Building, 500 Church St, Ann Arbor, MI 48109, USA 5 Departamento de Astronom´ıa, Universidad de Guanajuato, Guanajuato, Gto 36240, Mexico 6 ALMA SCO, Alonso de Córdova 3107, Vitacura, Santiago, Chile 7 Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland E-mail contact: osorio at iaa.es We present Very Large Array observations at 7 mm that trace the thermal emission of large dust grains in the HD 169142 protoplanetary disk. Our images show a ring of enhanced emission of radius ∼25-30 AU, whose inner region is devoid of detectable 7 mm emission. We interpret this ring as tracing the rim of an inner cavity or gap, possibly created by a planet or a substellar companion. The ring appears asymmetric, with the western part significantly brighter than the eastern one. This azimuthal asymmetry is reminiscent of the lopsided structures that are expected to be produced as a consequence of trapping of large dust grains. Our observations also reveal an outer annular gap at radii from ∼40 to ∼70 AU. Unlike other sources, the radii of the inner cavity, the ring, and the outer gap observed in the 7 mm images, which trace preferentially the distribution of large (mm/cm sized) dust grains, coincide with those obtained from a previous near-infrared polarimetric image, which traces scattered light from small (micron-sized) dust grains. We model the broad-band spectral energy distribution and the 7 mm images to constrain the disk physical structure. From this modeling we infer the presence of a small (radius ∼0.6 AU) residual disk inside the central cavity, indicating that the HD 169142 disk is a pre-transitional disk. The distribution of dust in three annuli with gaps in between them suggests that the disk in HD 169142 is being disrupted by at least two planets or substellar objects.

39 Accepted by ApJL http://arxiv.org/pdf/1407.6549

On the Onset of Secondary Stellar Generations in Giant Star Forming Regions and Massive Star Clusters J. Palous1, R. Wünsch1, and G. Tenorio-Tagle2 1 Astronomical Institute, Academy of Sciences of the Czech Republic, Bocn´ıII 1401, 141 31 Prague, Czech Republic 2 Instituto Nacional de Astrof´ısica Optica y Electrónica, AP 51, 72000 Puebla, México E-mail contact: palous at ig.cas.cz Here we consider the strong evolution experienced by the matter reinserted by massive stars, both in giant star forming regions driven by a constant star formation rate, and in massive and coeval superstar clusters. In both cases we take into consideration the changes induced by stellar evolution on the number of massive stars, the number of ionizing photons and the integrated mechanical luminosity of the star forming regions. The latter is at all times compared with the critical luminosity that defines, for a given size, the lower mechanical luminosity limit above which the matter reinserted via strong winds and supernova explosions suffers frequent and recurrent thermal instabilities that reduce its temperature and pressure and inhibit its exit as part of a global wind. Instead, the unstable reinserted matter is compressed by the pervasive hot gas, and photoionization maintains its temperature at T ∼ 104 K. As the evolution proceeds, more unstable matter accumulates and the unstable clumps grow in size. Here we evaluate the possible self-shielding of thermally unstable clumps against the UV radiation field. Self shielding allows for a further compression of the reinserted matter which rapidly develops a high density neutral core able to absorb in its outer skin the incoming UV radiation. Under such conditions the cold (T ∼ 10 K) neutral cores soon surpass the Jeans limit and become gravitationally unstable, causing a new stellar generation with the matter reinserted by former massive stars. We present the results of several calculations of this positive star formation feedback scenario promoted by strong radiative cooling and mass loading. Accepted by ApJ http://arxiv.org/pdf/1407.4247

On the Class II Methanol Maser Periodic Variability due to the Rotating Spiral Shocks in the Gaps of Disks Around Young Binary Stars S. Yu. Parfenov1 and A. M. Sobolev1 1 Ural Federal University, 51 Lenin Str., Ekaterinburg 620000, Russia E-mail contact: Sergey.Parfenov at urfu.ru We argue that the periodic variability of Class II methanol masers can be explained by variations of the dust temperature in the accretion disk around proto-binary star with at least one massive component. The dust temperature variations are caused by rotation of hot and dense material of the spiral shock wave in the disk central gap. The aim of this work is to show how different can be the Class II methanol maser brightness in the disk during the M oment of M aximum I llumination by the Spiral Shock material (hereafter MMISS) and the M oment when the disk is I lluminated by the Stars Only (MISO). We used the code CLOUDY (v13.02) to estimate physical conditions in the flat disk in the MISO and the MMISS. Model physical parameters of the disk were then used to estimate the brightness of 6.7, 9.9, 12.1 and 107 GHz masers at different impact parameters p using LVG approximation. It was shown that the strong masers experience considerable brightness increase during the MMISS with respect to MISO. There can happen both flares and dips of the 107 GHz maser brightness under the MMISS conditions, depending on the properties of the system. The brightest 9.9 GHz masers in the MMISS are situated at the greater p than the strong 6.7, 12.1 and 107 GHz masers that are situated at p< 200 AU. The brightness of 9.9 GHz maser in the MMISS suppressed at p< 200 AU and increase at p> 200 AU. Accepted by MNRAS http://arxiv.org/pdf/1407.7708

40 Characterizing the chemical pathways for water formation – A deep search for hydrogen peroxide B. Parise1, P. Bergman2 and K. Menten3 1 School of Physics and Astronomy, Cardiff University, UK 2 Onsala Space Observatory, Chalmers University of Technology, Sweden 3 Max-Planck-Institut für Radioastronomie, Germany E-mail contact: Berengere.Parise at astro.cf.ac.uk In 2011, hydrogen peroxide (HOOH) was observed for the first time outside the solar system (Bergman et al., A&A, 2011, 531, L8). This detection appeared a posteriori quite natural, as HOOH is an intermediate product in the formation of water on the surface of dust grains. Following up on this detection, we present a search for HOOH in a diverse sample of sources in different environments, including low-mass protostars and regions with very high column densities, such as Infrared Dark Clouds (IRDCs). We do not detect the molecule in any other source than Oph A, and derive 3σ upper limits for the abundance of HOOH relative to H2 lower than in Oph A for most sources. This result sheds a different light on our understanding of the detection of HOOH in Oph A, and shifts the puzzle to why this source seems to be special. Therefore we rediscuss the detection of HOOH in Oph A, as well as the implications of the low abundance of HOOH, and its similarity with the case of O2. Our chemical models show that the production of HOOH is extremely sensitive to the temperature, and favored only in the range 20−30 K. The relatively high abundance of HOOH observed in Oph A suggests that the bulk of the material lies at a temperature in the range 20−30 K. Accepted by Faraday Discussions 168 http://arxiv.org/pdf/1407.0550

Disk Radii and Grain Sizes in Herschel-Resolved Debris Disks Nicole Pawellek1, Alexander V. Krivov1, Jonathan P. Marshall2,3,4, Benjamin Montesinos5, Péter Abrahám´ 6 and Attila Moór6, Geoffrey Bryden7, and Carlos Eiroa8 1 Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena, Schillergäßchen 23, 07745 Jena, Germany 2 School of Physics, University of New South Wales, Sydney NSW 2052, Australia 3 Australian Centre for Astrobiology, University of New South Wales, Sydney, NSW 2052, Australia 4 Departamento de F´ısica Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain 5 Departmento de Astrof´ısica, Centro de Astrobiolog´ıa(CAB, CSIC-INTA), ESAC Campus, PO Box 78, 28691 Vil- lanueva de la Cañada, Madrid, Spain 6 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, PO Box 67, H-1525 Budapest, Hungary 7 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA 8 Departamento de F´ısica Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain E-mail contact: nicole.pawellek at uni-jena.de The radii of debris disks and the sizes of their dust grains are tracers of the formation mechanisms and physical processes operating in these systems. We use a sample of 34 debris disks spatially resolved in various Herschel programs to constrain them. While we modeled disks with both warm and cold components, we focus our analysis only on the cold outer disks, i.e. Kuiper-belt analogs. The disk radii derived from the resolved images reveal a large dispersion, but no significant trend with the stellar luminosity, which argues against ice lines as a dominant player in setting the debris disk sizes. Fixing the disk radii to those inferred from the resolved images, we model the spectral energy distributions to determine the dust temperatures and the grain size distributions. While the dust temperature systematically increases towards earlier spectral types, its ratio to the blackbody temperature at the disk radius decreases with the stellar luminosity. This is explained by an increase of typical grain sizes towards more luminous stars. The sizes are compared to the radiation pressure blowout limit sblow that is proportional to the stellar luminosity-to-mass ratio and thus also increases towards earlier spectral classes. The grain sizes in the disks of G- to

41 A-stars are inferred to be several times sblow at all stellar luminosities, in agreement with collisional models of debris disks. The sizes, measured in the units of sblow, appear to decrease with the luminosity, which may be suggestive of the disk’s stirring level increasing towards earlier-type stars. Accepted by ApJ http://arxiv.org/pdf/1407.4579

On the thermal sensitivity of binary formation in collapsing molecular clouds R. Riaz1, S.Z. Farooqui2, S. Vanaverbeke3,4 1 Institute of Space and Planetary Astrophysics (ISPA), University of Karachi, Karachi 75270, Pakistan 2 Faculty of Engineering Sciences, National University of Science Technology, Islamabad, Pakistan 3 Centre for mathematical Plasma-Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Heverlee, Belgium 4 Katholieke Universiteit Leuven Campus Kortrijk, E.-Sabbelaan 53, 8500 Kortrijk,Belgium E-mail contact: rafilriaz at yahoo.com We report the results of a numerical study on the initial formation stages of low-mass protostellar binary systems. We determine the separation of protostellar binaries formed as a function of the initial thermal state by varying the initial temperature in a slightly modified version of the Burkert and Bodenheimer collapse test. We find that the outcome is highly sensitive to both the initial temperature of the cloud and the initial amplitude of azimuthal density perturbation A. For A=10%, variations of only 1 unit Kelvin below 10 K lead to changes of up to 100 AU ( i.e. of order 30%) in the instantaneous separation, whereas for this small A the initial temperatures above 10 K yield, instead of a binary, a single low-mass fragment that never reaches protostellar densities. Protostellar binaries, however, do emerge when the perturbation amplitude is increased from 10% to 25%. We also investigate the impact of the critical density which governs the transition from isothermal to adiabatic thermodynamic behaviour of the collapsing gas. We find that the critical density not only affects the overall structural evolution of the gas envelope, but also the size of the rotating disk structures formed during collapse as well as the number of protostellar fragments resulting from the final fragmentation of the disks. This mechanism can give rise to young protostellar objects constituting bound multiple stellar systems. Accepted by MNRAS http://arxiv.org/pdf/1407.7115

Polarized Light Imaging of the HD 142527 Transition Disk with the Gemini Planet Imager: Dust around the Close-in Companion Timothy J. Rodigas1,4, Katherine B. Follette2, Alycia Weinberger1, Laird Close2, Dean C. Hines3 1 Department of Terrestrial Magnetism, Carnegie Institute of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, USA 2 Steward Observatory, The University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721, USA 3 Space Telescope Science Institute, Baltimore, MD 21218, USA 4 Carnegie Postdoctoral Fellow E-mail contact: trodigas at carnegiescience.edu When giant planets form, they grow by accreting gas and dust. HD 142527 is a young star that oﬀers a scaled-up view of this process. It has a broad, asymmetric ring of gas and dust beyond ∼100 AU and a wide inner gap. Within the gap, a low-mass stellar companion orbits the primary star at just ∼12 AU, and both the primary and secondary are accreting gas. In an attempt to directly detect the dusty counterpart to this accreted gas, we have observed HD 142527 with the Gemini Planet Imager in polarized light at Y band (0.95–1.14 µm). We clearly detect the companion in total intensity and show that its position and photometry are generally consistent with the expected values. We also detect a point-source in polarized light that may be spatially separated by ∼ a few AU from the location of the companion in total intensity. This suggests that dust is likely falling onto or orbiting the companion. Given the possible contribution of scattered light from this dust to previously reported photometry of the companion, the current mass limits should be viewed as upper limits only. If the dust near the companion is eventually conﬁrmed to be spatially separated, this

42 system would resemble a scaled-up version of the young planetary system inside the gap of the transition disk around LkCa 15. Accepted by ApJL http://arxiv.org/pdf/1407.7041

Champagne Flutes and Brandy Snifters: Modelling Protostellar Outflow-Cloud Chem- ical Interfaces R.P. Rollins1, J.M.C. Rawlings1, D.A. Williams1 and M.P. Redman2 1 Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom 2 Centre for Astronomy, School of Physics, National University of Ireland Galway, University Road, Galway, Ireland E-mail contact: rpr at star.ucl.ac.uk A rich variety of molecular species has now been observed towards hot cores in star forming regions and in the interstellar medium. An increasing body of evidence from millimetre interferometers suggests that many of these form at the interfaces between protostellar outflows and their natal molecular clouds. However, current models have remained unable to explain the origin of the observational bias towards wide-angled “brandy snifter” shaped outflows over narrower “champagne flute” shapes in carbon monoxide imaging. Furthermore, these wide-angled systems exhibit unusually high abundances of the molecular ion HCO+. We present results from a chemo-dynamic model of such regions where a rich chemistry arises naturally as a result of turbulent mixing between cold, dense molecular gas and the hot, ionized outflow material. The injecta drives a rich and rapid ion-neutral chemistry in qualitative and quantitative agreement with the observations. The observational bias towards wide-angled outflows is explained naturally by the geometry-dependent ion injection rate causing rapid dissociation of CO in the younger systems. Accepted by MNRAS http://arxiv.org/pdf/1407.2956

VLA and GBT Observations of Orion B (NGC 2024, W12) : Photo-dissociation Region Properties and Magnetic field D. Anish Roshi1, W. M. Goss2 and S. Jeyakumar3 1 National Radio Astronomy Observatory, Charlottesville & Green Bank, 520 Edgemont Road, Charlottesville, VA 22903, USA 2 National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801, USA 3 Departamento de Astronom´ıa, Universidad de Guanajuato, AP 144, Guanajuato CP 36000, Mexico E-mail contact: aroshi at nrao.edu We present images of C110α and H110α radio recombination line (RRL) emission at 4.8 GHz and images of H166α, C166α and X166α RRL emission at 1.4 GHz, observed toward the starforming region NGC 2024. The 1.4 GHz image ′′ ′′ with angular resolution ∼ 70 is obtained using VLA data. The 4.8 GHz image with angular resolution ∼ 17 is obtained by combining VLA and GBT data in order to add the short and zero spacing data in the uv plane. These images reveal that the spatial distributions of C110α line emission is confined to the southern rim of the H ii region close to the ionization front whereas the C166α line emission is extended in the north-south direction across the H ii region. The LSR velocity of the C110α line is 10.3 km s−1 similar to that of lines observed from molecular material located at the far side of the H ii region. This similarity suggests that the photo dissociation region (PDR) responsible for C110α line emission is at the far side of the H ii region. The LSR velocity of C166α is 8.8 km s−1. This velocity is comparable with the velocity of molecular absorption lines observed from the foreground gas, suggesting that the PDR is at the near side of the H ii region. Non-LTE models for carbon line forming regions are presented. Typical properties PDR −3 4 −3 of the foreground PDR are TPDR ∼ 100 K, ne ∼ 5 cm , nH ∼ 1.7 × 10 cm , path length l ∼ 0.06 pc and those PDR −3 5 −3 of the far side PDR are TPDR ∼ 200 K, ne ∼ 50 cm , nH ∼ 1.7 × 10 cm , l ∼ 0.03 pc. Our modeling indicates that the far side PDR is located within the H ii region. We estimate magnetic field strength in the foreground PDR to be 60 µG and that in the far side PDR to be 220 µG. Our field estimates compare well with the values obtained from OH Zeeman observations toward NGC 2024. The H166α spectrum shows narrow (1.7 km s−1) and broad (33

43 km s−1) line features. The narrow line has spatial distribution and central velocity (∼ 9kms−1) similar to that of the foreground carbon line emission, suggesting that they are associated. Modeling the narrow H166α emission provides PDR −3 −4 physical properties TPDR ∼ 50 K, ne ∼ 4 cm and l ∼ 0.01 pc and implies an ionization fraction of ∼ 10 . The broad H166α line originates from the H ii region. The X166α line has a diﬀerent spatial distribution compared to other RRLs observed toward NGC 2024 and is probably associated with cold dust clouds. Based on the expected low depletion of sulphur in such clouds and the −8.1 km s−1 velocity separation between X166α and C166α lines, we interpret that the X166α transition arises from sulphur. Accepted by ApJ http://arxiv.org/pdf/1408.0061

ALMA Observations of the T Tauri Binary System AS 205: Evidence for Molecular Winds and/or Binary Interactions Colette Salyk1, Klaus Pontoppidan2, Stuartt Corder3, Diego Muñoz4, Ke Zhang5, Geoffrey A. Blake5 1 National Optical Astronomy Observatory, 950 N Cherry Ave, Tucson, AZ 85719, USA 2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 3 Joint ALMA Observatory, Av. Alonso de Córdova 3107, Vitacura, Santiago, Chile 4 Center for Space Research, Department of Astronomy, Cornell University, Ithaca, NY 14853, USA 5 Division of Geological & Planetary Sciences, Mail Code 150-21, California Institute of Technology, Pasadena, CA 91125, USA E-mail contact: csalyk at gmail.com In this study, we present high-resolution millimeter observations of the dust and gas disk of the T Tauri star AS 205 N and its companion, AS 205 S, obtained with the Atacama Large Millimeter Array. The gas disk around AS 205 N, for which infrared emission spectroscopy demonstrates significant deviations from Keplerian motion that has been interpreted as evidence for a disk wind (Pontoppidan et al. 2011; Bast et al. 2011), also displays significant deviations from Keplerian disk emission in the observations presented here. Detections near both AS 205 N and S are obtained in 1.3 mm continuum, 12CO (2–1), 13CO 2–1 and C18O (2–1). The 12CO emission is extended up to 2′′ from AS 205N, and both 12CO and 13CO display deviations from Keplerian rotation at all angular scales. Two possible explanations for these observations hold up best to close scrutiny - tidal interaction with AS 205 S or disk winds (or a combination of the two), and we discuss these possibilities in some detail. Accepted by ApJ http://arxiv.org/pdf/1407.2652

Emission from Water Vapor and Absorption from Other Gases at 5–7.5 Microns in Spitzer-IRS Spectra of Protoplanetary Disks B.A. Sargent1,2, W. Forrest3, Dan M. Watson3, N. Calvet4, E. Furlan5,6, K.H. Kim3,7, J. Green8, K. Pontoppidan2, I. Richter3, C. Tayrien3,9 1 Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623, USA 2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 3 Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 4 Department of Astronomy, The University of Michigan, 500 Church Street, 830 Dennison Building, Ann Arbor, MI 48109, USA 5 National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719, USA 6 Visitor at the Infrared Processing and Analysis Center, Caltech, 770 South Wilson Avenue, Pasadena, CA 91125, USA 7 Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348, Republic of Korea 8 Department of Astronomy, University of Texas, 1 University Station, Austin, TX 78712, USA 9 Department of Computer Science, Rochester Institute of Technology, 102 Lomb Memorial Drive, Rochester, NY 14623, USA

44 E-mail contact: baspci at rit.edu We present spectra of 13 T Tauri stars in the Taurus-Auriga star-forming region showing emission in Spitzer Space Telescope Infrared Spectrograph (IRS) 5–7.5 µm spectra from water vapor and absorption from other gases in these stars’ protoplanetary disks. Seven stars’ spectra show an emission feature at 6.6 µm due to the ν2 = 1–0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures > 500 K, though some of these spectra also show indications of an absorption band, likely from another molecule. This water vapor emission contrasts with the absorption from warm water vapor seen in the spectrum of the FU Orionis star V1057 Cyg. The other six of the thirteen stars have spectra showing a strong absorption band, peaking in strength at 5.6–5.7 µm, which for some is consistent with gaseous formaldehyde (H2CO) and for others is consistent with gaseous formic acid (HCOOH). There are indications that some of these six stars may also have weak water vapor emission. Modeling of these stars’ spectra suggests these gases are present in the inner few AU of their host disks, consistent with recent studies of infrared spectra showing gas in protoplanetary disks. Accepted by ApJ http://arxiv.org/pdf/1407.2318

The three-dimensional structure of the Eta Carinae Homunculus W. Steffen1, M. Teodoro2, T.I. Madura2, J.H. Groh3, T.R. Gull2, A. Mehner4, M.F. Corcoran5,6, A. Damineli7, K. Hamaguchi5,8 1 Instituto de Astronom´ıa, UNAM, Apdo Postal 106, Ensenada 22800, Baja California, México 2 Astrophysics Science Division, Code 667, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 3 Geneva Observatory, Geneva University, Chemin des Maillettes 51, CH-1290, Sauverny, Switzerland 4 ESO, Alonso de Cordova 3107, Vitacura, Santiago de Chile, Chile 5 CRESST and X-ray Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 6 Universities Space Research Association, 7178 Columbia Gateway Drive, Columbia, MD 21046, USA 7 Instituto de Astronomia, Geof´ısica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitária, São Paulo, 05508-900, Brazil 8 Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA E-mail contact: wsteffen at astro.unam.mx We investigate, using the modeling code SHAPE, the three-dimensional structure of the bipolar Homunculus nebula surrounding Eta Carinae, as mapped by new ESO VLT/X-Shooter observations of the H2 λ = 2.12125 µm emission line. Our results reveal for the first time important deviations from the axisymmetric bipolar morphology: 1) circumpolar trenches in each lobe positioned point-symmetrically from the center and 2) off-planar protrusions in the equatorial region from each lobe at longitudinal (∼55◦) and latitudinal (10◦–20◦) distances from the projected apastron direction of the binary orbit. The angular distance between the protrusions (∼110◦) is similar to the angular extent of each polar trench (∼130◦) and nearly equal to the opening angle of the wind-wind collision cavity (∼110◦). As in previous studies, we confirm a hole near the centre of each polar lobe and no detectable near-IR H2 emission from the thin optical skirt seen prominently in visible imagery. We conclude that the interaction between the outflows and/or radiation from the central binary stars and their orientation in space has had, and possibly still has, a strong influence on the Homunculus. This implies that prevailing theoretical models of the Homunculus are incomplete as most assume a single star origin that produces an axisymmetric nebula. We discuss how the newly found features might be related to the Homunculus ejection, the central binary and the interacting stellar winds. We also include a 3D printable version of our Homunculus model. Accepted by MNRAS http://arxiv.org/pdf/1407.4096

Modelling MHD accretion-ejection - from the launching area to propagation scales Deniss Stepanovs1 and Christian Fendt1 1 Max Planck Institute for Astronomy, K¨onigstuhl 17, 69117 Heidelberg, Germany E-mail contact: stepanovs at mpia.de

45 We present results of axisymmetric magnetohydrodynamic (MHD) simulations investigating the launching of jets and outflows from a magnetically diffusive accretion disk. The time evolution of the disk structure is self-consistently taken into account. In contrast to previous works we have applied spherical coordinates for the numerical grid, implying substantial benefits concerning the numerical resolution and the stability of the simulation. Thanks to the new setup we were able to run simulations for more than 150,000 dynamical times on a domain extending 1500 inner disk radii with a resolution of up to 24 cells per disk height in the inner disk. Depending on the disk magnetization, jet launching occurs in two different but complementary regimes - jets driven predominantly by centrifugal or magnetic forces. These regimes differ in the ejection efficiency concerning mass, energy and angular momentum. We show that it is the actual disk magnetization and not so much the initial magnetization which describes the disk-jet evolution best. Considering the actual disk magnetization we also find that simulations starting with different initial magnetization evolve in a similar - typical - way as due to advection and diffusion the magnetic flux in the disk evolves in time. Exploring a new, modified diffusivity model we confirm the self-similar structure of the global jet-launching disk, obtaining power laws for the radial profiles of the disk physical variables such as density, magnetic field strength, or accretion velocity. Accepted by ApJ http://arxiv.org/pdf/1407.3136

The orbital motion of the Quintuplet cluster - a common origin for the Arches and Quintuplet clusters? Andrea Stolte1, Benjamin Hussmann1, Mark R. Morris2, Andrea M. Ghez2, Wolfgang Brandner3, Jessica R. Lu4, William I. Clarkson5, Maryam Habibi1 and Keith Matthews6 1 Argelander Institut fuer Astronomie, Auf dem Huegel 71, Bonn, Germany 2 Division of Astronomy and Astrophysics, UCLA, Los Angeles, CA 90095-1547, USA 3 Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, Heidelberg, Germany 4 Institute for Astronomy, University of Hawai’i, 2680 Woodlawn Drive, Honolulu, USA 5 Department of Natural Sciences, University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, USA 6 Caltech Optical Observatories, California Institute of Technology, MS 320-47, Pasadena, USA E-mail contact: astolte at astro.uni-bonn.de We investigate the orbital motion of the Quintuplet cluster near the Galactic center with the aim of constraining formation scenarios of young, massive star clusters in nuclear environments. Three epochs of adaptive optics high- angular resolution imaging with the Keck/NIRC2 and VLT/NAOS-CONICA systems were obtained over a time baseline of 5.8 years, delivering an astrometric accuracy of 0.5-1 mas/yr. Proper motions were derived in the cluster reference frame and were used to distinguish cluster members from the majority of the dense field star population toward the inner bulge. Fitting the cluster and field proper motion distributions with 2D gaussian models, we derive the orbital motion of the cluster for the first time. The Quintuplet is moving with a 2D velocity of 132 ± 15 km/s with respect to the field along the Galactic plane, which yields a 3D orbital velocity of 167 ± 15 km/s when combined with the previously known radial velocity. From a sample of 119 stars measured in three epochs, we derive an upper limit to the velocity dispersion in the core of the Quintuplet cluster of σ1D < 10 km/s. Knowledge of the three velocity components of the Quintuplet allows us to model the cluster orbit in the potential of the inner Galaxy. Under the assumption that the Quintuplet is located in the central 200 pc at the present time, these simulations exclude the possibility that the cluster is moving on a circular orbit. Comparing the Quintuplet’s orbit with our earlier measurements of the Arches orbit, we discuss the possibility that both clusters originated in the same area of the central molecular zone. According to the model of Binney et al. (1991), two families of stable cloud orbits are located along the major and minor axes of the Galactic bar, named x1 and x2 orbits, respectively. The formation locus of these clusters is consistent with the outermost x2 orbit and might hint at cloud collisions at the transition region between the x1 and x2 orbital families located at the tip of the minor axis of the Galactic bar. The formation of young, massive star clusters in circumnuclear rings is discussed in the framework of the channeling in of dense gas by the bar potential. We conclude that the existence of a large-scale bar plays a major role in supporting ongoing star and cluster formation, not only in nearby spiral galaxies with circumnuclear rings, but also in the Milky Way’s central molecular zone. Accepted by ApJ http://arxiv.org/pdf/1407.1854

46 The Enigma of the Open Cluster M29 (NGC 6913) Solved V. Straizys1, K. Milasius1, R.P. Boyle2, F.J. Vrba3, U. Munari4, N.R. Walborn5, K. Cernis1, A. Kazlauskas1, K. Zdanavicius1, R. Janusz6, J. Zdanavicius1 and V. Laugalys1 1 Institute of Theoretical Physics and Astronomy, Vilnius University, Gostauto 12, Vilnius LT-01108, Lithuania 2 Vatican Observatory Research Group, Steward Observatory, Tucson, AZ 85721, U.S.A. 3 U.S. Naval Observatory Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002, U.S.A. 4 INAF Astronomical Observatory of Padova, I-36012, Asiago (VI), Italy 5 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A. Operated by AURA, Inc., under NASA contract NAS5-26555 6 University School ‘Ignatianum’, Cracow, Poland E-mail contact: vytautas.straizys at tfai.vu.lt Determining the distance to the open cluster M29 (NGC 6913) has proven difficult, with distances determined by various authors differing by a factor of two or more. To solve this problem, we have initiated a new photometric investigation of the cluster in the Vilnius seven-color photometric system supplementing it with available data in the BV and JHKs photometric systems, and spectra of the nine brightest stars of spectral classes O and B. Photometric spectral classes and luminosities of 260 stars in a 15′ × 15′ area down to V = 19 mag are used to investigate the interstellar extinction run with distance and to estimate the distance of the Great Cygnus Rift, 800 pc. The interstellar reddening law in the optical and near-infrared regions is found to be close to normal, with the ratio of extinction to color excess RBV = 2.87. The extinction AV of cluster members is between 2.5 to 3.8 mag, with a mean value of 2.97 mag or EB−V = 1.03. The average distance of eight stars of spectral types O9–B2 is 1.54±0.15 kpc. Two stars from the seven brightest ones are field stars: HDE 229238 is a background B0.5 supergiant and HD 194378 is a foreground F star. In the intrinsic color-magnitude diagram, seven fainter stars of spectral classes B3–B8 are identified as possible members of the cluster. The 15 selected members of the cluster of spectral classes O9–B8 plotted on the log L/L⊙ vs. log Teff diagram, together with the isochrones from the Padova database, give the age of the cluster as 5±1 Myr. Accepted by AJ http://arxiv.org/pdf/1407.6291

Do cloud-cloud collisions trigger high-mass star formation? I. Small cloud collisions Ken Takahira1, Elizabeth J. Tasker1, and Asao Habe1 1 Department of Physics, Faculty of Science, Hokkaido University, Kita-ku, Sapporo 060-0810, Japan E-mail contact: tasker at astro1.sci.hokudai.ac.jp We performed sub-parsec (∼0.06 pc) scale simulations of two idealised molecular clouds with different masses undergoing a collision. Gas clumps with density greater than 10−20 g cm−3 (0.3 × 104 cm−3) were identified as pre-stellar cores and tracked through the simulation. The colliding system showed a partial gas arc morphology with core formation in the oblique shock-front at the collision interface. These characteristics support NANTEN observations of objects suspected to be colliding giant molecular clouds (GMCs). We investigated the effect of turbulence and collision speed on the resulting core population and compared the cumulative mass distribution to cores in observed GMCs. Our results suggest that a faster relative velocity increases the number of cores formed but that cores grow via accretion predominately while in the shock front, leading to a slower shock being more important for core growth. The core masses obey a power law relation with index γ = −1.6, in good agreement with observations. This suggests that core production through collisions should follow a similar mass distribution as quiescent formation, albeit at a higher mass range. If cores can be supported against collapse during their growth, the estimated ram pressure from gas infall is of the right order to counter the radiation pressure and form a star of 100 M⊙. Accepted by ApJ http://arxiv.org/pdf/1407.4544

47 Circumbinary Ring, Circumstellar disks and accretion in the binary system UY Aurigae Ya-Wen Tang1, Anne Dutrey2, Stéphane Guilloteau2, Vincent Pietu3, Emmanuel Difolco2, , Tracy Beck4, Paul T.P. Ho1, Yann Boehler5, Fréderic Gueth3, Jeff Bary6, Michal Simon7 1 Academia Sinica, Institute of Astronomy and Astrophysics, Taipei, Taiwan 2 Universitéde Bordeaux, Observatoire Aquitain des Sciences de l’Univers, CNRS, UMR 5804, Laboratoire d’Astrophysique de Bordeaux, 2 rue de l’Observatoire, BP 89, F-33271 Floirac Cedex, France 3 IRAM, 300 rue de la piscine, F-38406 Saint Martin dH‘eres Cedex, France 4 Space Telescope Science Institute,3700 san Martin Dr. Baltimore, MD 21218, USA 5 Centro de Radioastronom´ıay Astrof´ısica, UNAM, Apartado Postal 3-72, 58089 Morelia, Michoacán, Mexico 6 Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA 7 Stony Brook University, Stony Brook, NY 11794-3800, USA E-mail contact: ywtang at asiaa.sinica.edu.tw Recent exo-planetary surveys reveal that planets can orbit and survive around binary stars. This suggests that some fraction of young binary systems which possess massive circumbinary disks (CB) may be in the midst of planet formation. However, there are very few CB disks detected. We revisit one of the known CB disks, the UY Aurigae system, and probe 13CO 2–1, C18O 2–1, SO 5(6)–4(5) and 12CO 3–2 line emission and the thermal dust continuum. Our new results confirm the existence of the CB disk. In addition, the circumstellar (CS) disks are clearly resolved in dust continuum at 1.4 mm. The spectral indices between the wavelengths of 0.85 mm and 6 cm are found to be surprisingly low, being 1.6 for both CS disks. The deprojected separation of the binary is 1′′. 26 based on our 1.4 mm continuum data. This is 0′′. 07 (10 AU) larger than in earlier studies. Combining the fact of the variation of UY Aur B in R band, we propose that the CS disk of an undetected companion UY Aur Bb obscures UY Aur Ba. A very complex kinematical pattern inside the CB disk is observed due to a mixing of Keplerian rotation of the CB disk, the infall and outflow gas. The streaming gas accreting from the CB ring toward the CS disks and possible outflows are also identified and resolved. The SO emission is found to be at the bases of the streaming shocks. Our results suggest that the UY Aur system is undergoing an active accretion phase from the CB disk to the CS disks. The UY Aur B might also be a binary system, making the UY Aur a triple system. Accepted by ApJ http://arxiv.org/pdf/1407.4561

Spatially resolved HCN J=4-3 and CS J=7-6 emission from the disk around HD 142527 G. van der Plas1,2, S. Casassus1,2, F. Menard2,3,4, S. Perez1,2, W. F. Thi3, C. Pinte3,4 and V. Christiaens1,2 1 Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile 2 Millenium Nucleus Protoplanetary Disks in ALMA Early Science, Universidad de Chile, Casilla 36-D, Santiago, Chile 3 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble, France 4 UMI FCA, CNRS / INSU France, and Dept. de Astronomia y Obs. Astronomico Nacional, Universidad de Chile, Casilla 36-D, Correo Central, Santiago, Chile ( UMI 3386 ) E-mail contact: info at gerritvanderplas.com The disk around HD 142527 attracts a lot of attention, amongst others because of its resolved (sub) mm dust continuum that is concentrated into a horseshoe-shape towards the north of the star. In this manuscript we present spatially resolved ALMA detections of the HCN J=4-3 and CS J=7-6 emission lines. These lines give us a view deeper into the disk compared to the (optically thicker) CO isotopes. This is the ﬁrst detection of CS J=7-6 coming from a protoplanetary disk. Both emission lines are azimuthally asymmetric and are suppressed under the horseshoe-shaped continuum emission peak. A possible mechanism to explain the decrease under the horseshoe-shaped continuum is the increased opacity coming from the higher dust concentration at the continuum peak. Lower dust and/or gas temperatures and an optically thick radio-continuum reduce line emission by freeze-out and shielding of emission from the far side of the disk. Accepted by ApJ Letters http://arxiv.org/pdf/1407.1735

48 The origin of organic emission in NGC 2071 T.A. van Kempen1, C. McCoey2, S. Tisi2, D. Johnstone3,4,5, and M. Fich2 1 Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, the Netherlands 2 Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada 3 Joint Astronomy Centre, 660 North A’ohoku Place, University Park, Hilo, HI 96720, USA 4 National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Rd, Victoria, BC, V9E 2E7, Canada 5 Department of Physics & Astronomy, University of Victoria, Victoria, BC, V8P 1A1, Canada E-mail contact: kempen at strw.leidenuniv.nl Context: The physical origin behind organic emission in embedded low-mass star formation has been fiercely debated in the last two decades. A multitude of scenarios have been proposed, from a hot corino to PDRs on cavity walls to shock excitation. Aims: The aim of this paper is to determine the location and the corresponding physical conditions of the gas responsible for organics emission lines. The outflows around the small protocluster NGC 2071 are an ideal testbed to differentiate between various scenarios. Methods: Using Herschel-HIFI and the SMA, observations of CH3OH, H2CO and CH3CN emission lines over a wide range of excitation energies were obtained. Comparisons to a grid of radiative transfer models provide constraints on the physical conditions. Comparison to H2O line shape is able to trace gas-phase synthesis versus a sputtered origin. Results: Emission of organics originates in three spots: the continuum sources IRS 1 (‘B’) and IRS 3 (‘A’) as well 7 −3 as a outflow position (‘F’). Densities are above 10 cm and temperatures between 100 to 200 K. CH3OH emission observed with HIFI originates in all three regions and cannot be associated with a single region. Very little organic emission originates outside of these regions. Conclusions: Although the three regions are small (<1,500 AU), gas-phase organics likely originate from sputtering of ices due to outflow activity. The derived high densities (>107 cm−3) are likely a requirement for organic molecules to survive from being destroyed by shock products. The lack of spatially extended emission confirms that organic molecules cannot (re)form through gas-phase synthesis, as opposed to H2O, which shows strong line wing emission. The lack of CH3CN emission at ‘F’ is evidence for a different history of ice processing due to the absence of a protostar at that location and recent ice mantle evaporation. Accepted by A&A http://arxiv.org/pdf/1407.2426

Mapping accretion and its variability in the young open cluster NGC 2264: a study based on u-band photometry L. Venuti1,2,3, J. Bouvier1,2, E. Flaccomio4, S. H. P. Alencar5, J. Irwin6, J. R. Stauffer7, A. M. Cody7, P. S. Teixeira8, A.P. Sousa5, G. Micela4, J.-C. Cuillandre9 and G. Peres3 1 Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France 2 CNRS, IPAG, F-38000 Grenoble, France 3 Dipartimento di Fisica e Chimica, Universitàdegli Studi di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy 4 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Palermo G.S. Vaiana, Piazza del Parlamento 1, 90134 Palermo, Italy 5 Departamento de F´ısica - ICEx - UFMG, Av. Antônio Carlos, 6627, 30270-901 Belo Horizonte, MG, Brazil 6 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 7 Spitzer Science Center, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA 8 Universität Wien, Institut für Astrophysik, Türkenschanzstrasse 17, 1180, Vienna, Austria 9 Canada - France - Hawaii Telescope Corporation, 65-1238 Mamalahoa Highway, Kamuela, HI, 96743, USA E-mail contact: Laura.Venuti at obs.ujf-grenoble.fr The accretion process has a central role in the formation of stars and planets. We aim at characterizing the accretion properties of several hundred members of the star-forming cluster NGC 2264 (3 Myr). We performed a deep ugri mapping as well as a simultaneous u-band+r-band monitoring of the star-forming region with CFHT/MegaCam in order to directly probe the accretion process onto the star from UV excess measurements. Photometric properties and

49 stellar parameters are determined homogeneously for about 750 monitored young objects, spanning the mass range ∼0.1–2 M⊙. About 40% of the sample are classical (accreting) T Tauri stars, based on various diagnostics (Hα, UV and IR excesses). The remaining non-accreting members define the (photospheric + chromospheric) reference UV emission level over which flux excess is detected and measured. We revise the membership status of cluster members based on UV accretion signatures, and report a new population of 50 CTTS candidates. A large range of UV excess is measured for the CTTS population, varying from a few times 0.1 to ∼3 mag. We convert these values to accretion luminosities and accretion rates, via a phenomenological description of the accretion shock emission. We thus obtain −10 −7 mass accretion rates ranging from a few 10 to ∼10 M⊙/yr. Taking into account a mass-dependent detection threshold for weakly accreting objects, we find a >6σ correlation between mass accretion rate and stellar mass. A 1.4±0.3 power-law fit, properly accounting for censored data (upper limits), yields M˙ acc ∝ M∗ . At any given stellar mass, we find a large spread of accretion rates, extending over about 2 orders of magnitude. The monitoring of the UV excess on a timescale of a couple of weeks indicates that its variability typically amounts to 0.5 dex, i.e., much smaller than the observed spread in accretion rates. We suggest that a non-negligible age spread across the star-forming region may effectively contribute to the observed spread in accretion rates at a given mass. In addition, different accretion mechanisms (like, e.g., short-lived accretion bursts vs. more stable funnel-flow accretion) may be associated to different M˙ acc regimes. A huge variety of accretion properties is observed for young stellar objects in the NGC 2264 cluster. While a definite correlation seems to hold between mass accretion rate and stellar mass over the mass range probed here, the origin of the large intrinsic spread observed in mass accretion rates at any given mass remains to be explored. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1408.0432

Observations of nitrogen isotope fractionation in deeply embedded protostars Susanne F. Wampfler1,2, Jes K. Jørgensen2,1, Martin Bizzarro1 and Suzanne E. Bisschop1,2 1 Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 København K, Denmark 2 Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 København Ø, Denmark E-mail contact: wampfler at nbi.dk Context: The terrestrial planets, comets, and meteorites are significantly enriched in 15N compared to the Sun and Jupiter. While the solar and jovian nitrogen isotope ratio is believed to represent the composition of the protosolar nebula, a still unidentified process has caused 15N-enrichment in the solids. Several mechanisms have been proposed to explain the variations, including chemical fractionation. However, observational results that constrain the fractionation models are scarce. While there is evidence of 15N-enrichment in prestellar cores, it is unclear how the signature evolves into the protostellar phases. Aim: The aim of this study is to measure the 14N/15N ratio around three nearby, embedded low- to intermediate-mass protostars. Methods: Isotopologues of HCN and HNC were used to probe the 14N/15N ratio. A selection of J=3-2 and 4-3 transitions of H13CN, HC15N, HN13C, and H15NC was observed with the Atacama Pathfinder EXperiment telescope (APEX). The 14N/15N ratios were derived from the integrated intensities assuming a standard 12C/13C ratio. The assumption of optically thin emission was verified using radiative transfer modeling and hyperfine structure fitting. Results: Two sources, IRAS 16293A and R CrA IRS7B, show 15N-enrichment by a factor of ∼ 1.5 − 2.5 in both HCN and HNC with respect to the solar composition. IRAS 16293A falls in the range of typical prestellar core values. Solar composition cannot be excluded for the third source, OMC-3 MMS6. Furthermore, there are indications of a trend toward increasing 14N/15N ratios with increasing outer envelope temperature. Conclusions: The enhanced 15N abundances in HCN and HNC found in two Class 0 sources (14N/15N ∼ 160 − 290) and the tentative trend toward a temperature-dependent 14N/15N ratio are consistent with the chemical fractionation scenario, but 14N/15N ratios from additional tracers are indispensable for testing the models. Spatially resolved observations are needed to distinguish between chemical fractionation and isotope-selective photochemistry. Accepted by A&A http://arxiv.org/pdf/1408.0285

50 The Discovery of a Very Massive Star in W49 Shi-Wei Wu1,5, Arjan Bik1,2, Thomas Henning1, Anna Pasquali3, Wolfgang Brandner1 and Andrea Stolte4 1 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany 2 Department of Astronomy, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm, Sweden 3 Universität Heidelberg, Zentrum für Astronomie, Astronomisches Recheninstitut, Mönchhofstrasse 12-14, 69120 Heidelberg, Germany 4 Argelander Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany 5 International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg (IMPRS-HD) E-mail contact: shiwei at mpia.de

Very massive stars (M > 100 M⊙) are very rare objects, but have a strong influence on their environment. The formation of this kind of objects is of prime importance in star formation, but observationally still poorly constrained. We report on the identification of a very massive star in the central cluster of the star-forming region W49. We investigate near-infrared K-band spectroscopic observations of W49 from VLT/ISAAC together with JHK images obtained with NTT/SOFI and LBT/LUCI. We derive a spectral type of W49nr1, the brightest star in the dense core of the central cluster of W49. On the basis of its K-band spectrum, W49nr1 is classified as an O2-3.5If* star with a K-band absolute magnitude of -6.27±0.10 mag. The effective temperature and bolometric correction are estimated from stars of similar spectral type. After comparison to the Geneva evolutionary models, we find an initial mass between 100 M⊙ and 180 M⊙. Varying the extinction law results in a larger initial mass range of 90 - 250 M⊙. Accepted by A&A Letters http://arxiv.org/pdf/1407.4804v1.pdf

A study of dynamical processes in the Orion KL region using ALMA– Probing molecular outflow and inflow Yuefang Wu1, Tie Liu2, and Sheng-Li Qin3 1 Department of Astronomy, Peking University, 100871,Beijing China 2 Korea Astronomy and Space Science Institute 776, Daedeokdae- ro, Yuseong-gu, Daejeon, Republic of Korea 305-348 3 School of Physical Science and Technology, Yunnan University, Kunming,650091,China E-mail contact: ywu at pku.edu.cn This work reports a high spatial resolution observations toward Orion KL region with high critical density lines of CH3CN (124–114) and CH3OH (81,8–70,7) as well as continuum at ∼1.3 mm band. The observations were made using the Atacama Large Millimeter/Submillimeter Array with a spatial resolution of ∼1′′. 5 and sensitives about 0.07 K and ∼0.18 K for continuum and line, respectively. The observational results showed that the gas in the Orion KL region consists of jet-propelled cores at the ridge and dense cores at east and south of the region, shaped like a wedge ring. The outflow has multiple lobes, which may originate from an explosive ejection and is not driven by young stellar objects. Four infrared bubbles were found in the Spitzer/IRAC emissions. These bubbles, the distributions of the previously found H2 jets, the young stellar objects and molecular gas suggested that BN is the explosive center. The burst time was estimated to be ≤ 1300 years. In the mean time, signatures of gravitational collapse toward Source I and hot core were detected with material infall velocities of 1.5 km s−1 and ∼0.6 km s−1, corresponding to mass −3 −1 −5 −1 accretion rates of 1.2 × 10 M⊙ yr and 8.0 × 10 M⊙ yr , respectively. These observations may support that high-mass stars form via accretion model, like their low-mass counterparts. Accepted by ApJ http://arxiv.org/pdf/1407.8370

Star formation associated with a large-scale infrared bubble Jin-Long Xu1,2 and Bing-Gang Ju3,4 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2 NAOC-TU Joint Center for Astrophysics, Lhasa 850000, China

51 3 Purple Mountain Observatory, Qinghai Station, 817000, Delingha, China 4 Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, China E-mail contact: xujl at bao.ac.cn Using the data from the Galactic Ring Survey (GRS) and Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE), we performed a study for a large-scale infrared bubble with a size of about 16 pc at a distance of 2.0 kpc. We present the 12CO J = 1–0, 13CO J = 1–0 and C18O J = 1–0 observations of HII region G53.54−0.01 (Sh2−82) obtained at the the Purple Mountain Observation (PMO) 13.7 m radio telescope to investigate the detailed distribution of associated molecular material. The large-scale infrared bubble shows a half-shell morphology at 8 µm. H II regions G53.54−0.01, G53.64+0.24, and G54.09−0.06 are situated on the bubble. Comparing the radio recombination line velocities and associated 13CO J = 1–0 components of the three H II regions, we found that the 8 µm emission associated with H II region G53.54−0.01 should belong to the foreground emission, and only overlap with the large-scale infrared bubble in the line of sight. Three extended green objects (EGOs, the candidate massive young stellar objects), as well as three H II regions and two small-scale bubbles are found located in the G54.09−0.06 complex, indicating an active massive star-forming region. C18O J = 1–0 emission presents four cloud clumps on the northeastern border of H II region G53.54−0.01. Via comparing the spectral proﬁles of 12CO J = 1–0, 13CO J = 1–0, and C18O J = 1–0 peak at each clump, we found the collected gas in the three clumps, except for the clump coincided with a massive YSO (IRAS 19282+1814). Using the evolutive model of H II region, we derived that the age of H II region G53.54−0.01 is 1.5 × 106 yr. The signiﬁcant enhancement of several Class I and Class II YSOs around G53.54−0.01 indicates the presence of some recently formed stars, which may be triggered by this H II region through the collect and collapse (CC) process. Accepted by A&A http://arxiv.org/pdf/1407.6819

On the Feeding Zone of Planetesimal Formation by the Streaming Instability Chao-Chin Yang1 and Anders Johansen1 1 Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, SE-22100 Lund, Sweden E-mail contact: ccyang at astro.lu.se The streaming instability is a promising mechanism to overcome the barriers in direct dust growth and lead to the formation of planetesimals. Most previous studies of the streaming instability, however, were focused on a local region of a protoplanetary disk with a limited simulation domain such that only one filamentary concentration of solids has been observed. The characteristic separation between filaments is therefore not known. To address this, we conduct the largest-scale simulations of the streaming instability to date, with computational domains up to 1.6 gas scale heights both horizontally and vertically. The large dynamical range allows the effect of vertical gas stratification to become prominent. We observe more frequent merging and splitting of filaments in simulation boxes of high vertical extent. We find multiple filamentary concentrations of solids with an average separation of about 0.2 local gas scale heights, much higher than the most unstable wavelength from linear stability analysis. This measures the characteristic separation of planetesimal forming events driven by the streaming instability and thus the initial feeding zone of planetesimals. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1407.5995

ALMA Observations of Infalling Flows toward the Keplerian Disk around the Class I Protostar L1489 IRS Hsi-Wei Yen1, Shigehisa Takaku1, Nagayoshi Ohashi1,2, Yuri Aikawa3, Yusuke Aso4, Shin Koyamatsu4,2, Masahiro N. Machida5, Kazuya Saigo6, Masao Saito7, Kengo Tomida8,9 and Kohji Tomisaka10,11 1 Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan 2 Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720, USA 3 Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501, Jap 4 Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo

52 113-0033, Japan 5 Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan 6 Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan 7 Joint ALMA Observatory, Ave. Alonso de Cordova 3107, Vitacura, Santiago, Chile 8 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA 9 Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan 10 Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Osawa, Mitaka, Tokyo 181-8588, Japan 11 National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588, Japan E-mail contact: hwyen at asiaa.sinica.edu.tw 12 18 We have conducted ALMA observations in the 1.3 mm continuum and CO (2–1), C O (2–1) and SO (56–45) lines toward L1489 IRS, a Class I protostar surrounded by a Keplerian disk and an infalling envelope. The Keplerian 12 18 disk is clearly identified in the CO and C O emission, and its outer radius (∼700 AU) and mass (∼0.005 M⊙) are comparable to those of disks around T Tauri stars. The protostellar mass is estimated to be 1.6 M⊙ with the inclination angle of 66◦. In addition to the Keplerian disk, there are blueshifted and redshifted off-axis protrusions seen in the C18O emission pointing toward the north and the south, respectively, adjunct to the middle part of the Keplerian disk. The shape and kinematics of these protrusions can be interpreted as streams of infalling flows with a conserved angular momentum following parabolic trajectories toward the Keplerian disk, and the mass infalling rate −7 −1 −3 is estimated to be ∼5 × 10 M⊙ yr . The specific angular momentum of the infalling flows (∼2.5 × 10 km s−1 pc) is comparable to that at the outer radius of the Keplerian disk (∼4.8 × 10−3 km s−1 pc). The SO emission is elongated along the disk major axis and exhibits a linear velocity gradient along the axis, which is interpreted as that the SO emission primarily traces a ring region in the flared Keplerian disk at radii of ∼250–390 AU. The local enhancement of the SO abundance in the ring region can be due to the accretion shocks at the centrifugal radius where the infalling flows fall onto the disk. Our ALMA observations unveiled both the Keplerian disk and the infalling gas onto the disk, and the disk can further grow by accreting material and angular momenta from the infalling gas. Accepted by ApJ http://arxiv.org/pdf/1407.2699

Search for free-floating planetary-mass objects in the Pleiades M.R. Zapatero Osorio1, M.C. Gálvez Ortiz1, G. Bihain2, C.A.L. Bailer-Jones3, R. Rebolo4,5, Th. Henning3, S. Boudreault6, V.J.S. Béjar4,5, B. Goldman3, R. Mundt3, and J.A. Caballero7 1 Centro de Astrobiolog´ıa(CSIC-INTA), Carretera de Ajalvir km 4, E-28850 Torrejón de Ardoz, Madrid, Spain 2 Leibniz-Institut fr Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482, Potsdam, Germany 3 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany 4 Instituto de Astrofsica de Canarias, Va Láctea s/n, E-38205 La Laguna, Tenerife, Spain 5 Dept. Astrofsica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain 6 GEPI, Observatoire de Paris, CNRS, Universit Paris Diderot; 5 Place Jules Janssen, F-92190 Meudon, France 7 Centro de Astrobiolog´ıa(CSIC-INTA), PO Box 78, E-28691 Villanueva de la Cañada, Madrid, Spain E-mail contact: mosorio at cab.inta-csic.es We aim at identifying the least massive population of the solar metallicity, young (120 Myr), nearby (133.5 pc) Pleiades star cluster with the ultimate goal of understanding the physical properties of intermediate-age, free-floating, low-mass brown dwarfs and giant planetary-mass objects, and deriving the cluster substellar mass function across the deuterium-burning mass limit at ∼0.012 M⊙. We performed a deep photometric and astrometric J- and H-band survey covering an area of ∼0.8 deg2. The images with completeness and limiting magnitudes of J,H ≈ 20.2 and ≈ 21.5 mag were acquired ∼9 yr apart (proper motion precision of ±6 mas yr−1). J- and H-band data were complemented with Z, K, and mid-infrared magnitudes up to 4.6 µm coming from UKIDSS, WISE, and follow-up observations of our own. Pleiades member candidates were selected to have proper motions compatible with that of the cluster, and colors following the known Pleiades sequence in the interval J = 15.5–8.8 mag, and ZUKIDSS − J > 2.3 mag or Z nondetections for J > 18.8 mag. We found a neat sequence of astrometric and photometric Pleiades substellar member candidates in the intervals J = 15.5–21.2 mag and ∼0.072-0.008 M⊙. The faintest objects show very red near- and mid-infrared colors exceeding those of field high-gravity dwarfs by > 0.5 mag. The Pleiades photometric

53 sequence does not show any color turn-over because of the presence of photospheric methane absorption down to J = 20.3 mag, which is about 1 mag fainter than predicted by the color-computed models. Pleiades brown dwarfs have a proper motion dispersion of 6.4–7.5 mas yr−1 and are dynamically relaxed at the age of the cluster. The Pleiades mass function extends down to the deuterium burning-mass threshold, with a slope fairly similar to that of other young star clusters and stellar associations. Accepted by A&A http://arxiv.org/pdf/1407.2849

Magnetic Fields and Massive Star Formation Qizhou Zhang1, Keping Qiu2, Josep M. Girart3, Hauyu (Baobab) Liu4, Ya-Wen Tang4, Patrick M. Koch4, Zhi-Yun Li5, Eric Keto1, Paul T.P. Ho1,4, Ramprasad Rao4, Shih-Ping Lai6,4, Tao-Chung Ching1,6, Pau Frau7, How-Huan Chen1, Hua-Bai Li8, Marco Padovani9, Sylvain Bontemps10, Timea Csengeri11, Carmen Juárez3 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA 2 School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, Nanjing 210093, China 3 Institut de Ciéncies de l’Espai, (CSIC-IEEC), Campus UAB, Facultat de Ciéncies, C5p 2, 08193 Bellaterra, Catalonia 4 Academia Sinica Institute of Astronomy and Astrophysics, P. O. Box 23-141, Taipei, 106 Taiwan 5 Department of Astronomy, University of Virginia, P. O. Box 400325, Charlottesville, VA 22904, USA 6 Institute of Astronomy and Department of Physics, National Tsing Hua University, 101 Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan 7 Observatorio Astronómico Nacional, Alfonso XII, 3 E-28014 Madrid, Spain 8 Department of Physics, The Chinese University of Hong Kong 9 Laboratoire de Radioastronomie Millimétrique, UMR 8112 du CNRS, Ecole´ Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, 75231 Paris Cedex 05, France 10 OASU/LAB-UMR5804, CNRS, UniversitéBordeaux 1, 33270 Floirac, France 11 Max Planck Institute for Radioastronomy, Auf dem Hügel 69, 53121 Bonn, Germany E-mail contact: qzhang at cfa.harvard.edu

Massive stars (M > 8 M⊙) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 µm obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of ∼< 0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within 40◦ of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly < 3 oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks (∼10 AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scale of 0.01–0.1 pc in the context of massive star and cluster star formation. Accepted by ApJ http://arxiv.org/pdf/1407.3984

Discovery of a pre-existing molecular ﬁlament associated with supernova remnant G127.1+0.5 Xin Zhou1,2, Ji Yang1,2, Min Fang1,2, and Yang Su1,2 1 Purple Mountain Observatory, CAS, 2 West Beijing Road, Nanjing 210008, China 2 Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, China E-mail contact: xinzhou at pmo.ac.cn

54 We performed millimeter observations in CO lines toward the supernova remnant (SNR) G127.1+0.5. We found a molecular filament at 4–13 km s−1 consisting of two distinct parts: a straight part coming out of the remnant region and a curved part in the remnant region. The curved part is coincides well with the bright SNR shell detected in 1420 MHz radio continuum and mid-infrared observations in the northeastern region. In addition, redshifted line wing broadening is found only in the curved part of the molecular filament, which indicates a physical interaction. These provide strong evidences, for the first time, to confirm the association between an SNR and a pre-existing long molecular filament. Multi-band observations in the northeastern remnant shell could be explained by the interaction between the remnant shock and the dense molecular filament. RADEX radiative transfer modeling of the quiet and shocked components yield physical conditions consistent with the passage of a non-dissociative J-type shock. We argue that the curved part of the filament is fully engulfed by the remnant’s forward shock. A spatial correlation between aggregated young stellar objects (YSOs) and the adjacent molecular filament close to the SNR is also found, which could be related to the progenitor’s activity. Accepted by ApJ http://arxiv.org/pdf/1407.6746

Echography of young stars reveals their evolution K. Zwintz1, L. Fossati2, T. Ryabchikova3, D. Guenther4, C. Aerts1,5, T.G. Barnes6, N. Themeßl7, D. Lorenz7, C. Cameron8, R. Kuschnig7, S. Pollack-Drs7, E. Moravveji1, A. Baglin9, J. M. Matthews10, A.F.J. Moffat11, E. Poretti12, M. Rainer12, S.M. Rucinski13 , D. Sasselov14, W.W. Weiss7 1 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium 2 Argelander Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany 3 Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow, Russia 4 Department of Astronomy and Physics, St. Mary’s University, Halifax, NS B3H 3C3, Canada 5 Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands 6 The University of Texas at Austin, McDonald Observatory, 82 Mt. Locke Rd., McDonald Observatory, Texas 79734, USA 7 Universität Wien, Institut für Astrophysik, Türkenschanzstraße 17, 1180 Vienna, Austria 8 Department of Mathematics, Physics & Geology, Cape Breton University, 1250 Grand Lake Road, Sydney, Nova Scotia, Canada, B1P 6L2 9 LESIA, Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195, Meudon, France 10 Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada 11 Départment de Physique, Universitéde Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7, Canada 12 INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy 13 Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, ON M5S 3H4, Canada 14 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA E-mail contact: konstanze.zwintz at ster.kuleuven.be We demonstrate that a seismic analysis of stars in their earliest evolutionary phases is a powerful method to identify young stars and distinguish their evolutionary states. The early star that is born from the gravitational collapse of a molecular cloud reaches at some point sufficient temperature, mass and luminosity to be detected. Accretion stops and the pre-main sequence star that emerges is nearly fully convective and chemically homogeneous. It will continue to contract gravitationally until the density and temperature in the core are high enough to start nuclear burning of hydrogen. We show that there is a relationship between detected pulsation properties for a sample of young stars and their evolutionary status illustrating the potential of asteroseismology for the early evolutionary phases. Accepted by Science http://arxiv.org/pdf/1407.4928

55 Meetings

MIRA Conference on Circumstellar Disks and Planet Formation October 12-14, 2014 University of Michigan, Ann Arbor, MI

Recent developments in astrophysics and geophysics include improvements in our understanding of star formation, the discovery of thousands of extrasolar planets, and new insights into the accretion and early diﬀerentiation of Earth- like planets. Circumstellar disks provide the link between these topics, as most of the mass of the forming star is accreted through the disk, which also provides the initial conditions for planet formation and subsequent migration and evolution. The conference will address disk formation, structure and evolution; planet formation, dynamics, structure, and diﬀerentiation; and properties of exoplanets. Invited speakers include Kassandra Anderson (Cornell University), Sean Andrews (Center for Astrophysics), Phil Ar- mitage (University of Colorado), Konstantin Batygin (CalTech), Richard W. Carlson (Carnegie Institution of Wash- ington), John Chambers (Carnegie Institution of Washington), Fred Ciesla (University of Chicago), Ilse Cleeves (Uni- versity of Michigan), Catherine Espaillat (Boston University), Kaitlin Kratter (University of Arizona), Stefan Kraus (University of Exeter), Hal Levison (Southwest Research Institute), William F. McDonough (University of Maryland), Burkhard Militzer (University of California, Berkeley), Richard Nelson (Queen Mary, University of London), Karin Oberg¨ (Harvard University), Sascha Quanz (ETH Zurich), Emily Rauscher (University of Michigan), David Steven- son (Caltech), Lars Stixrude (University College London), John Tobin (National Radio Astronomy Observatory), Neal Turner (Jet Propulsion Laboratory - Caltech), Kevin Walsh (Southwest Research Institute), Jonathan Williams (University of Hawaii), Yanqin Wu (University of Toronto), Andrew Youdin (University of Arizona), Zhaohuan Zhu (Princeton University) Conference Information and Registration are available at http://www.lsa.umich.edu/mira/workshopsconferences/circumstellardisksandplanetformationconference

Reminder: Star Formation Across Space and Time 11-14 November 2014 ESA/ESTEC, Noordwijk, The Netherlands

The objective of this meeting is to bring together astronomers interested in all aspects of star formation, from local galactic to extreme extra-galactic high-z conditions. Recent advances on the subject suggest various communities can beneﬁt from each other, and the meeting aims to facilitate cross-fertilization between researchers with diﬀerent observational and theoretical backgrounds to further our understanding of star formation as observed across the spectrum. The meeting poses the fundamental question: Are there universal processes of star formation across space and time? The deadline for abstract submission is 28 August 2014 All information about the conference is available at: http://congrexprojects.com/14a09/ Welcome!

56 Filamentary Structure in Molecular Clouds A NORTH AMERICAN ALMA SCIENCE CENTER (NAASC) WORKSHOP 10-11 October 2014 Charlottesville, Virginia NRAO is pleased to announce that registration is open for the North American ALMA Science Workshop ”Filamentary Structure in Molecular Clouds” at Note that registration is only $75 USD for this two-day meeting. We encourage you to register early, as space is limited to 60 attendees by the auditorium size. Please submit abstracts for contributed papers by 1 August for consideration by the SOC to select as contributed talks or posters. Poster abstracts are also being accepted. We look forward to seeing you in Charlottesville! WORKSHOP WEBSITE: https://science.nrao.edu/science/meetings/2014/filamentary-structure/ WORKSHOP SCIENTIFIC GOALS: Filamentary structure in clouds has been observed dating back many years. In addition, numerical hydrodynamic and MHD simulations of clouds over the past 15 years have consistently shown that filamentary structure is always present, and may be produced by turbulence and self-gravity. Recent Herschel observations of nearby dust clouds have highlighted that the dense gas is distributed predominantly in filaments. Filamentary structure may be ubiquitous in the internal structure of all molecular clouds and may be preferential formation sites of the dense cores that eventually collapse to form stars. If such filamentary structures were universal in all molecular clouds with low and high mass star formation, then the entire paradigm of cloud formation and evolution leading to star formation would be placed on a framework that centers on cloud condensation into filaments and filament fragmentation into cores. Filaments and embedded cores may also develop simultaneously, as suggested by some numerical simulations. It will be important for observational studies of star formation in molecular clouds to delineate the conditions, including magnetic fields, and the time sequence for the formation and evolution of dense filaments and cores within them. This two-day science workshop will be held at NRAO Headquarters in Charlottesville, Virginia on 10-11 October 2014, where the attendees will present and discuss the current evidence for or against the picture described above. Importantly, it is hoped that the attendees will formulate future observational and theoretical investigations to define further the nature, origin and evolution of such filamentary structures. WORKSHOP FORMAT: The workshop aims to stimulate discussions of outstanding issues and future studies. A few short review talks (30 minutes total, including 5 minutes for Q&A) will set the stage, but contributed papers are encouraged, especially from postdoctoral fellows and students. The Scientific Organizing Committee (SOC) will select some papers for contributed talks (10 minutes plus 5 minutes for Q&A) and will select others as posters that will be displayed throughout the meeting. Ample time will be set aside for panel-audience discussions, as well as for coffee breaks and lunches to allow viewing and discussion of posters. Please visit the workshop website for additional information or contact the SOC Chair (Fred Lo, flo AT nrao.edu) if you have questions. SCIENTIFIC ORGANIZING COMMITTEE (SOC): Fred Lo, Chair (NRAO), Crystal Brogran (NRAO), Paola Caselli (MPE), Neal Evans (Texas), James di Francesco (HIA), Paul Goldsmith (JPL/Caltech), Mark Heyer (UMass), Zhi Yun Li (Virginia), Lee Mundy (CARMA), Phil Myers (CfA), Eve Ostriker (Princeton), Juergen Ott (NRAO), Enrique Vazquez (UNAM) KEY WORKSHOP DATES AND DEADLINES: Registration Opens: 18 Jul Abstract Due: 1 Aug Final Scientific Program: 15 Aug Hotel Reservation Deadlines: 9 Sep (Red Roof), 18 Sep (Marriott) Registration Closes: 19 Sep

57 Summary of Upcoming Meetings

StarBench-II: A Workshop for Benchmarking Star Formation Codes 1 - 5 September 2014 Bonn, Germany http://www.astro.uni-bonn.de/sb-ii/ Planet Formation and Evolution 2014 8 - 10 September 2014 Kiel, Germany http://www.astrophysik.uni-kiel.de/kiel2014 Living Together: Planets, Stellar Binaries and Stars with Planets 8 - 12 September 2014 Litomysl Castle, Litomysl, Czech Republic http://astro.physics.muni.cz/kopal2014/ Galactic and Extragalactic Star Formation 8 - 12 September 2014 Marseille, France http://gesf2014.lam.fr Thirty Years of Beta Pic and Debris Disk Studies 8 - 12 September 2013 Paris, France http://betapic30.sciencesconf.org Towards Other Earths II. The Star-Planet Connection 15 - 19 September 2014 Portugal http://www.astro.up.pt/toe2014 Filamentary Structure in Molecular Clouds 10 - 11 October 2014 Charlottesville, USA https://science.nrao.edu/science/meetings/2014/filamentary-structure/ MIRA Conference on Circumstellar Disks and Planet Formation 12 - 14 October 2014 Ann Arbor, USA http://www.lsa.umich.edu/mira/workshopsconferences/circumstellardisksandplanetformationconference The Early Life of Stellar Clusters: Formation and Dynamics 3 - 7 November 2014, Copenhagen, Denmark http://www.nbia.dk/nbia-clusters-2014 Star Formation Across Space and Time 11-14 November 2014 Noordwijk, The Netherlands http://congrexprojects.com/14a09/ Triple Evolution & Dynamics in Stellar and Planetary Systems 15 - 21 November 2014 Haifa, Israel http://trendy-triple.weebly.com 45th “Saas-Fee Advanced Course”: From Protoplanetary Disks to Planet Formation 15-20 March 2015, Switzerland http://isdc.unige.ch/sf2015 The Soul of Massive Star Formation 15 - 20 March 2015 Puerto Varas, Chile http://www.das.uchile.cl/msf2015/ Star and Planet Formation in the Southwest 23 - 27 March 2015 Oracle, Arizona, USA no website yet

58 Disk dynamics and planet formation 29 June - 3 July 2015 Larnaka, Cyprus http://www.star.uclan.ac.uk/discs2015 Extreme Solar Systems III 29 November - 4 December 2015 Hawaii, USA http://ciera.northwestern.edu/Hawaii2015.php The 19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun 6 - 10 June 2016 Uppsala, Sweden http://www.coolstars19.com Other meetings: http://www1.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/meetings/

Short Announcements

Fizeau exchange visitors program - call for applications

The Fizeau exchange visitors program in optical interferometry funds (travel and accommodation) visits of researchers to an institute of his/her choice (within the European Community) to perform collaborative work and training on one of the active topics of the European Interferometry Initiative. The visits will typically last for one month, and strengthen the network of astronomers engaged in technical, scientific and training work on optical/infrared interferometry. The program is open for all levels of astronomers (Ph.D. students to tenured staff). non-EU based missions will only be funded if considered essential by the Fizeau Committee. Applicants are strongly encouraged to seek also partial support from their home or host institutions. The deadline for applications is September 15. Fellowships can be awarded for missions starting in November 2014. Fur- ther informations and application forms can be found at www.european-interferometry.eu and vltischool.sciencesconf.org The program is funded by OPTICON/FP7. Looking forward to your applications, Josef Hron & Laszlo Mosoni (for the European Interferometry Initiative) Electronic mail: fi[email protected]

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