258 — 6 June 2014 Editor: Bo Reipurth ([email protected]) List of Contents

258 — 6 June 2014 Editor: Bo Reipurth (Reipurth@Ifa.Hawaii.Edu) List of Contents

THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 258 — 6 June 2014 Editor: Bo Reipurth ([email protected]) List of Contents

The Star Formation Newsletter Interview ...... 3 My Favorite Object ...... 5 Editor: Bo Reipurth [email protected] Perspective ...... 8

Technical Editor: Eli Bressert Abstracts of Newly Accepted Papers ...... 12 [email protected] Abstracts of Newly Accepted Major Reviews . 41 Technical Assistant: Hsi-Wei Yen Meetings ...... 42 [email protected] New and Upcoming Meetings ...... 44

Editorial Board

Joao Alves Alan Boss Jerome Bouvier Cover Picture Lee Hartmann Thomas Henning The cover shows a first-light image with ESO’s Paul Ho SPHERE - the Spectro-Polarimetric High-contrast Jes Jorgensen Exoplanet REsearch instrument mounted on the Charles J. Lada VLT. SPHERE’s main goal is to find and character- Thijs Kouwenhoven ize giant exoplanets orbiting nearby stars by direct Michael R. Meyer imaging. SPHERE combines adaptive optics with Ralph Pudritz a coronagraph and differential imaging. The image Luis Felipe Rodr´ıguez shows the well known dust ring around HR4796A, a Ewine van Dishoeck probable member of the TW Hya association. The Hans Zinnecker star, which is a component in a 7.7 arcsec visual binary, is young, about 8 Myr, with a spectral type of The Star Formation Newsletter is a vehicle for A0 V. It is surrounded by a dust ring with a radius fast distribution of information of interest for as- of 75 AU. tronomers working on star and planet formation and molecular clouds. You can submit material Image courtesy ESO/J.-L. Beuzit et al./SPHERE for the following sections: Abstracts of recently Consortium 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 Ph.D dissertations), Meetings (announcing meetings broadly of interest to the star and planet for- Submitting your abstracts mation and early solar system community), New Jobs (advertising jobs specifically aimed towards Latex macros for submitting abstracts persons within the areas of the Newsletter), and and dissertation abstracts (by e-mail to Short Announcements (where you can inform or re- [email protected]) are appended to quest information from the community). Addition- each Call for Abstracts. You can also ally, the Newsletter brings short overview articles submit via the Newsletter web inter- on objects of special interest, physical processes or face at http://www2.ifa.hawaii.edu/star- theoretical results, the early solar system, as well formation/index.cfm as occasional interviews. Newsletter Archive www.ifa.hawaii.edu/users/reipurth/newsletter.htm

2 population plus a supermassive black hole (conservatively, we called it a central mass point), with a mass of about Luis Felipe Rodr´ıguez five million solar masses. However, this evidence for the in conversation with Bo Reipurth existence of a supermassive black hole at the center of the Milky Way was not considered fully convincing, since the kinematics of gas can be affected by things such as supernova explosions and pressure gradients. As we all know, most astronomers became convinced of the presence of a supermassive black hole there with the fantastic work of the groups of Reinhard Genzel and Andrea Ghez, that was made with the motion of stars and was unquestionable. Q: How did you become an expert in centimeter radio interferometry? A: In the last two years of my Ph. D. I realized that to get high angular resolution information in the radio you needed, of course, to learn interferometry. I started working under the guidance of Jim Moran, one of the world’s foremost experts in the field. I remember our first trip to the yet uncompleted Very Large Array in New Mexico to Q: Who was your Ph. D. thesis adviser and what was your do observations of the surroundings of Herbig-Haro can- thesis about? didates, searching for their exciting sources. I learned a A: I did my undergraduate thesis in Physics at the Na- lot from Jim, as well as from the very knowledgeable staff tional University of Mexico, under the direction of Silvia of the US National Radio Astronomy Observatory. I still Torres-Peimbert (who is now President-elect of the Inter- publish occassionally with Jim and, yes, I am still learning national Astronomical Union). The thesis was on ioniza- from him. tion structures of planetary nebulae, a topic of optical as- Q: You have studied thermal radio jets in many regions. tronomy with a long tradition in my country. At that time What have you learned about the collimation and other (1974) we did not have graduate programs in Astronomy parameters of such jets? in Mexico, so I applied and was accepted at Harvard. A: The study of thermal jets has been very useful. They I left for Harvard with the belief that I was going to con- locate accurately the position of the exciting sources of tinue working on optical astronomy, but after taking the outflows and allow the study of the phenomenon very close first classes I was astounded by the relevance of multiwave- to the young star. One can also get an estimate of the ion- length astronomy and decided that I had to learn one of ized mass loss rate and of the direction of the gas ejected these relatively new astronomies and later start it in Mex- by the system in the last years or decades. The observa- ico. Interestingly, Riccardo Giaconni was my first adviser tions suggest that within 100 AU or so from the star the at Harvard and I guess I could have specialized in X-ray jet has modest collimation, but that collimation increases astronomy, but in those days I got the impression that to farther away. In particular, most HH objects suggest high do observational work in this spectral window you needed collimation at large distances from the exciting star. to be in the USA or Europe and I wanted to return to my country. So, the obvious choice was radio astronomy, that Q: You have used the VLA extensively to study Herbig- was mature enough for one to be able to do research from Haro objects and their driving sources. Especially the clas- any place in the world, using well-established facilities. sical system HH 1/2 has provided beautiful results. Are you continuing these studies? My Ph. D. thesis adviser was Eric Chaisson, an expert in single-dish observations and in the study of radio recom- A: Indeed, HH 1/2 has been a key object in the study of bination lines. Since a lot of work was already done in the outflow phenomenon in star formation. They were the studying galactic HII regions in the recombination lines, first HH objects, discovered by Herbig and Haro back in we decided to study the ionized gas around the galactic the 1950s. The 1981 paper of Herbig and Jones reporting center. The recombination lines from this region are much large diverging proper motions for these two objects indi- wider (hundreds of km/sec) than those of normal galactic cated that they shared an exciting source, somewhere in HII regions (tens of km/sec) and combining our data with between them. We were part of the US-Mexico collabora- line observations of other tracers we came to the conclu- tion that in 1986 reported the VLA detection of a radio sion that the kinematics of the ionized gas around Sgr A* source right at the middle of the system, that was iden- was best explained by a combination of the known stellar tified as the exciting source. These and other important

3 contributions consolidated a new paradigm for star for- Q: Your team have measured proper motions of the Becklin- mation, in which the forming star not only accretes gas, Neugebauer object and Radio Source I in Orion. What are but also ejects it in collimated jets that produce the HH your conclusions, and are you continuing to study this re- objects and the bipolar molecular outflows. gion? Q: You have published many papers on the Cepheus A A: Luis Zapata, a young researcher at our Center, leads outflow region. What makes this region so interesting? this effort. As the star-disk paradigm becomes stronger A: Cepheus A is very important because it was the first as an explanation for the formation of stars of all masses, high-mass young star that exhibited similar phenomena on the other hand we have this amazing region where an to that seen in low-mass protostars, that is, collimated explosion that can be observed in the gas and stars took outflows and the possible presence of a circumstellar disk. place some 500 years ago and may point to the formation These results pointed to the idea that stars of all masses of a close binary or even to the fusion of two stars. We need share the same formation mechanism. to find more examples of these explosions and understand what they mean. Recently, Luis reported a similar case Q: Among the many Herbig-Haro energy sources you have in DR21, so perhaps they are not as rare as previously studied, L1551 IRS5 has been the subject of many of your thought. We are searching for other examples. analyses. What have you learned by studying this source? Q: You and Felix Mirabel have discovered and studied a A: For many years we all thought that L1551 IRS5 was number of relativistic jets inside our Galaxy. a single star, producing a single outflow. However, in the 1990s it became clear that it was a relatively close binary A: During a sabbatical I took at the VLA, I had the op- system (with a projected separation in the sky of about portunity of discovering the first example of superluminal 45 AU), with each star having its own disk and its own motions for a galactic source. These sources are X-ray jet system. We learnt that star formation via the disk- binaries that are sometimes called microquasars because jet combination is a very robust mechanism, taking place they mimic, in small scale, the phenomena observed in even in close binary systems. quasars. Felix believed that jets should be present in stellar mass black holes (as they are in supermassive black Q: You and Salvador Curiel and other team members have holes at the centers of galaxies) and this work showed that discovered and studied the Serpens triple radio source. What the physics around black holes is similar, regardless of the makes this source so special? mass of the black hole. A: The Serpens triple is a neat system that clearly shows Q: You founded the UNAM-Morelia Center, with a strong proper motions. It was also one of the first systems that focus on star formation studies, and you were director for showed evidence of non-thermal (synchrotron) emission in many years. Was that a difficult process, and how is the its lobes. I have had the pleasure to work with other ob- Center doing? servers such as Salvador Curiel, JoséM. Torrelles, and yourself, as well as with theoreticians like Jorge Cantó, A: I hate doing administration, but sometimes it is im- Susana Lizano, Alex Raga and Paola D’Alessio. Star for- possible to avoid it. I was first Director of the big Mexico mation is one of the strongest science fields in Mexico, City Astronomy institute and later, Yolanda Gómez, Su- thanks to the contribution of many researchers. sana Lizano, Stan Kurtz, Enrique Vázquez, myself and other colleagues started the Morelia Center. It was a dif- Q: Laurent Loinard and you and other team members have ficult process because resources are scarce in Mexico and used radio parallaxes to determine distances to nearby star the established institutions always see the new ones as po- forming regions with unprecedented accuracy. How accu- tential competitors. Altogether, the experience has been rate can this be done, and how many regions are amenable very rewarding for all of us. The Center is small (about 20 to such analysis? researchers) but the bibliometric indicators place us as one A: For the best cases, one can get accuracies below 1%. I of the Mexican institutions with the largest international love to give my radio parallax talk to physicists, who usu- impact. ally believe that astronomy is an order of magnitude sci- Q: Astronomy has in recent years been suffering all over ence, and are shocked by these results. Laurent does this the world due to the financial crisis. What is the situation work using the compact gyrosynchrotron emission from ac- for Mexican astronomy? tive magnetospheres of low-mass young stars. Mark Reid and Karl Menten head a similar effort that uses maser A: The investment in science in Mexico is not only small emission and is better suited for regions of massive star but many times it is also poorly used. In terms of peo- formation. The synchrotron technique is good to a few ple, we have a great potential, but we have to get better kpc and the maser technique can be applied to most of organized and use these modest resources wisely. the galaxy.

4 Evolutionary state of Chamaeleon-MMS1

My Favorite Object The question of the evolutionary state of Cha-MMS1 is Chamaeleon-MMS1 important, because the core might be an example of a very transient stage in star formation. Originally Larson Miikka Väisälä (1969) predicted a stage in the core collapse, where after the initial collapse the internal pressure within the core would grow strong enough to resist the collapse. How- ever, this first hydrostatic core would last a relatively short time (within a few thousand years) until the dissociation of molecular hydrogen would allow the core to collapse even further. Belloche et al. (2006) have suggested that Cha-MMS1 is at the stage just prior to the Class 0 stage, namely FHSC. First, they suspect this because of deuterium fractiona- + [N2D ] tion. Their observed fractionation, + = 11 3%, [N2H ] ± comes between the fractionation observed in L1544 (16 23%) and L1521F (5 10%) (Crapsi et al. 2005), a known− Class 0 protostar. In− addition, they see no sign of molec- Chamaeleon-MMS1 (Cha-MMS1) is a very young proto- ular outflow originating from Cha-MMS1. Instead they stellar core which is associated with the reflection nebula attribute the origin of Herbig-Haro objects HH 49/50 to Cederblad 110 located in the centre of the Chamaeleon I the Class I protostar Ced 110 IRS 4, instead of Cha-MMS1 (Cha I) cloud complex. Cederblad 110 is considered to be as suggested originally by Reipurth et al. (1996). Further- an active site of star formation within Cha I (e.g., Prusti et more, Tsitali et al. (2013) point out that the 70 µm flux al. 1991; Persiet al. 2001). As such, Cha-MMS1 is located density of the central source would imply a very low lumi- near a small cluster of young stellar objects (YSOs) called nosity which in turn would be consistent with an FHSC, Ced 110 IRS2, IRS4, and IRS6. Distance to Cha-MMS1 as it would be clearly too low for a true protostar. is 160 pc which makes it a relatively nearby object. A On the other hand, Cha-MMS1 has a large abundance look∼ into some features of the core and its environment of carbon-chain-bearing species, in similar amounts com- can be seen in the Fig. 1. pared to other carbon-chair-rich interstellar clouds (Cor- Cha-MMS1 was discovered by Reipurth et al. (1996), diner et al. 2012). This may hint that oxygen is frozen-out based on a λ = 1.3 mm survey. It is a cold, dense core within the core, but another option is that the core might which is particularly interesting, because it has been sug- be heated by a protostar inside. gested by Belloche et al. (2006, 2011), Cordiner et al. In Väisäläet al. (2013) we analysed the SED of Cha- (2012) and Tsitali et al. (2013) to be still in the first hydro- MMS1 by fitting model SEDs to the observed flux den- static core (FHSC, see Larson 1969) stage of development. sities. The model SEDs were based on YSO models by As the FSHC is such a brief stage within the process of core Robitaille et al. (2006, 2007) which consists of a grid of collapse, Cha-MMS1 might provide a rare opportunity to 20 000 two-dimensional YSO radiation transfer models. observe this phenomenon. And to add more complexity The best fit acquired suggests the luminosity of 0.6 L⊙, in the mix, Cha-MMS1 is apparently hit by a molecular which is higher than what just a FHSC would produce. As outflow emitted by Ced110 IRS4 (Hiramatsu et al. 2007; such, the model indicates that the Cha-MMS1 would have Ladd et al. 2011). Cha-MMS1 being virially unstable, the reached already to the Class 0 stage. However, the data outflow could further destabilize the core against collapse. point at 70 µm does not fit very well with the models, and My personal interest concerning the Cha-MMS1 is con- the models of Robitaille et al. (2006) only cover YSOs with nected with our study based on high-resolution ammonia central temperatures above 2000 K. As Commer¸con et al. observations of the Cha-MMS1 with the Australian Tele- (2012) suggests, it is very difficult to distinguish between scope Compact Array or ATCA (Väisäläet al. 2014). In FHSCs and Class 0 YSOs just based on SED information. our study, we found that the ammonia core possesses a However, an observation of a molecular outflow might not rotating bar-like structure, and we considered the possi- settle the question either. It is theoretically feasible that bility that a very early stage molecular outflow could be a slow, weakly collimated outflow might be produced al- present deep within the core. ready during the FHSC stage of core collapse (see e.g. Machida et al. 2008). There exists some candidate outflows from FHSCs or very low luminosity objects such as

5 Figure 1: Left: Intensity of thermal dust emission at the wavelength λ = 250 µm in a region of 5′ 5′ around Cha-MMS1. The Spitzer 24-µm peak is indicated with a red triangle. The red circle in the top right cor×responds to the average Herschel beamsize (FWHM, 18′′) at 250 µm. The small white ellipse shows the synthesised ATCA beam ( 7′′). Middle: Dust temperature in the same region. The red circle in the top right represents the resolution of ∼ ′′ the calculated Tdust and H2 column density maps (40 ). Right: H2 column density derived from the 250-µm optical thickness. The dust temperature and column density maps are derived by fitting a modified blackbody function to the Herschel intensity maps. The locations of three prominent YSOs, Ced110 IRS2 (right), IRS4 (middle), and IRS6 (left), are indicated with asterisks. The plus sign indicates the location of the millimetre source Cha-MMS1a (Reipurth −1 et al. 1996). The white contour shows the integrated intensity level5Kkms of the NH3(1, 1) satellites as observed −1 with ATCA. The yellow contours show the integrated intensity of the NH3(1, 1) line emission (K km s ) observed at Parkes Radio Telescope. The Parkes beam is shown with the large yellow circle in the top right. (Credit: Väisäläet al., A&A, 564, A99, 2014, reproduced with permission c ESO.)

L673-7 (Dunham et al. 2010), Per-Bolo 58 (Enoch et al. inside. The elongated geometry of the excited component 2010; Dunham et al. 2011), L1448 IRS 2E (Chen et al. could be caused by an early molecular outflow seen nearly 2010); L1451 (Pineda et al. 2011), CB 17 MMS (Chen in the plane of the sky. The projected total length of the et al. 2012), and L1521F-IRS (Takahashi et al. 2013), al- hypothetical outflow is approximately 9000 AU. though also in these cases making a distinction between an We also found tentative 1.3 cm continuum emission aligned FHSC and a very low luminosity Class 0 object is difficult. with the assumed rotation axis (Väisäläet al. 2014). This string of weak sources near the ammonia maximum is only Presence of an outflow? 3–4 times stronger than the rms noise in the area. There- fore, this observation should be confirmed, or disproved Considering the state of the evolution of the Cha-MMS1 by more sensitive observations of the 1.3 cm continuum. core, the question of outflow still remains. Despite that Regardless, such emission could be a result of shocked gas Belloche et al. (2006) do not see any clear signs of out- due to outflow within the core. flows, some features of our NH3 (1, 1) observations have No CO outflow originating in Cha-MMS1 has been de- made us to ask the question if an actual early stage molec- tected. If there is indeed an outflow present, the likely ular outflow could really be present within the core. It reason for non-detection is that the high-velocity wings of would be reasonable to consider the presence of an out- the spectra may still be confined in the very inner regions flow even in the case of FHSC, because such candidates of the core. Therefore, it can have escaped the previous exist. single-dish surveys.

By making a two-layer fit to the NH3 (1, 1) spectral lines, However, with our observations we cannot conclusively we found that the background component is highly excited confirm a presence of an outflow cavity within the core. A along the axis of rotation (see Fig. 2, Väisäläet al. 2014). more definitive solution would require more detailed and This hints toward a presence of some energetic process sensitive observations.

6 2014). However, perhaps the steeper velocity gradient in the northeast part of the core might be explained by an indirect collision of the outﬂow. Alternatively we see a bar-like density distribution with apparent rotation, where ammonia shows strong signs of self-absorption.

Things to look for

Although there are reasons to consider the presence of an outflow within Cha-MMS1, our ammonia observations by themselves cannot confirm the existence of it. There- fore, future high-resolution observations, such as a search for a compact CO outflow, could likely either confirm or deny its existence. In addition, probing the distribution and kinematics of dense gas in the neighbourhood of the Spitzer 24 µm source would be fruitful, perhaps even of- fering some insight into how the collision from the IRS4 outflow dynamically affects the whole system. References: Belloche, A., Parise, B., van der Tak, F. F. S., et al. 2006, A&A, Figure 2: The region where the two-layer fit is applicable 454, L51 is shown with white diamonds on the integrated bright- Belloche, A., Schuller, F., Parise, B., et al. 2011, A&A, 527, A145 ness temperature map of the NH (1, 1) satellites. Blue Chen, X., Arce, H. G., Zhang, Q., et al. 2010, ApJ, 715, 1344 3 Chen, X., Arce, H. G., Dunham, M. M., et al. 2012, ApJ, 751, 89 plus signs indicate positions where Tex,bg > 11 K, i.e., Commer¸con, B., Launhardt, R., Dullemond, C., Henning, T. 2012, where the excitation temperature of the background com- A&A, 545, A98 ponent exceeds the average kinetic temperature of the Cordiner, M. A., Charnley, S. B., Wirström, E. S., Smith, R. G. core. (Credit: Väisäläet al., A&A, 564, A99, 2014, re- 2012, ApJ, 744, 131 Crapsi, A., Caselli, P., Walmsley, C. M., Myers, P. C., Tafalla, M., produced with permission c ESO.) Lee, C. W., Bourke, T. L. 2005, ApJ, 619, 379 Dunham, M. M., Evans, N. J., Bourke, T. L., et al. 2010, ApJ, 721, 995 Dunham, M. M., Chen, X., Arce, H. G., et al. 2011, ApJ, 742, 1 Interaction with Ced 110 IRS4 outflow Enoch, M. L., Lee, J.-E., Harvey, P., Dunham, M. M., Schnee, S. 2010, ApJ, 722, L33 Hiramatsu, M., Hayakawa, T., Tatematsu, K., et al. 2007, ApJ, 664, Regardless of outflow within the Cha-MMS1 core itself, 964 observations by Hiramatsu et al. (2007) and Ladd et al. Ladd, E. F., Wong, T., Bourke, T. L., Thompson, K. L. 2011, ApJ, (2011) have shown that the blueshifted lobe of the out- 743, 108 flow from the Ced 110 IRS 4 collides with the Cha-MMS1 Larson, R. B. 1969, MNRAS, 145, 271 Machida, M. N., Inutsuka, S.-i., Matsumoto, T. 2008, ApJ, 676, 1088 core. In addition Ladd et al. (2011) state that some of Persi, P., Marenzi, A. R., Gómez, M., Olofsson, G. 2001, A&A, 376, the material is displaced by the collision between the core 907 and the outflow. Here, Ladd et al. (2011) consider two Pineda, J. E., Arce, H. G., Schnee, S., et al. 2011, ApJ, 743, 201 possibilities: a direct collision or a glancing blow. Their Prusti, T., Clark, F. O., Whittet, D. C. B., Laureijs, R. J., Zhang, C. Y. 1991, MNRAS, 251, 303 analysis supports more of the glancing blow scenario. Reipurth, B., Nyman, L.-., Chini, R. 1996, A&A, 314, 258 The reason for this is due to the ablated material by the Robitaille, T. P., Whitney, B. A., Indebetouw, R., Wood, K., Denz- more, P. 2006, ApJS, 167, 256 collision. With a direct collision, the outflow would have Robitaille, T. P., Whitney, B. A., Indebetouw, R., Wood, K. 2007, enough momentum to just plough through the core. In ApJS, 169, 328 case of the direct collision a ”splash” may be produced, Takahashi, S., Ohashi, N., Bourke, T. L. 2013, ApJ, 774, 20 which might explain the displaced material. However, Tsitali, A. E., Belloche, A., Commeron, B., Menten, K. M. 2013, A&A, 557, A98 Ladd et al. (2011) do not see any sign of interaction in Väisälä, M.S., Harju, J., Mantere, M.J., Miettinen, O., Sault, R. S., + the bulk of N2H emission from Cha-MMS1, which should Walmsley, C.M., Whiteoak, J. B. 2014, A&A, 564, 99 be present considering the direction of HH 49/50, if the collision was indeed a direct one. In our high-resolution ammonia emission map, we do not see any strong signs of a direct collision (Väisäläet al.

7 AU from the star, where considerable planet-forming mass may reside. Disk temperatures are constrained by infrared Perspective spectral energy distributions, but these probe only the surface temperatures of disks and not the more important Observing Protoplanetary temperatures at the midplanes. Disk mass is constrained Disks using Chondrules by the flux emitted at millimeter wavelengths, provided the solid particles emitting the radiation are smaller than Steve Desch millimeter-sized (e.g., Eisner & Carpenter 2006); but such observations are blind to any solids mass locked up in planets. While the Atacama Large Millimeter Array may change the picture, observations until now have lacked the spatial resolution to measure surface densities within 10 AU. For the same reason it has not been possible to∼ observe spiral shocks in protoplanetary disks that might indicate angular momentum transport through gravitational instabilities. Astronomical observations alone cannot supply all the information needed to model planet formation. Instead, meteorites can supply an enormous amount of information about protoplanetary disks, at least the one our solar system formed from. They can be analyzed for elemental and isotopic compositions, with precisions that are astounding compared to astronomical data, usually at the parts per million level. Radiometric dating of meteorites is how we know that the solar system and Sun formed 4568 The properties of protoplanetary disks are difficult to probe Myr ago (Bouvier & Wadhwa 2010), and many events can with astronomical observations. Meteorites one can hold be timed to within 105 years (a precision < 0.01%!). in one’s hand provide a wealth of specific detail about the In combination with∼ astrophysical modeling, one can infer conditions and physical properties in disks. As much about the pressures, temperatures, and physical processes acting disks has been learned from microscopes as from telescopes... in the protoplanetary disk. My purpose here is to describe the type of data obtained from meteorites, especially from chondrules within chondrites (unmelted meteorites), and 1 Telescopes vs. microscopes to explain what such measurements and models have revealed about our protoplanetary disk. Protoplanetary disks have been recognized as the birth- places of planets and solar systems since Laplace and Kant, but detailed data took until the 20th century to acquire 2 Data about chondrule formation and are still incomplete. To understand disk evolution and The study of meteorites has traditionally divided along the formation of planets, modelers need such information disciplinary lines. Developing quantitative physical mod- as the mass Md of the disk, and the surface density Σ(r) els to describe events in the Sun’s protoplanetary disk is and temperature T (r) within the disk as functions of dis- the domain of the astrophysicists, but often this commu- tance r from the star. Modelers also require constraints nity is unaware of the richness of meteoritic data. Partly on the mechanisms of angular momentum transport in the this is because the rocks themselves are described by me- disk and the timescales over which the disk mass is lost teoriticists with backgrounds in geology, using jargon and and accreted onto the central star. These data are difficult terminology that initially can be opaque to astrophysi- to obtain through astronomical observation. cists. But the essential information, as follows, is eas- Only in recent decades have astronomical observations ily learned. Meteorites are asteroid fragments that inter- supplied some of this information, and our knowledge re- cept the Earth. Asteroids that melt from internal heating mains incomplete. Just to see the silhouetted protoplan- by radionuclides produce iron meteorites or stony achon- etary disks in the Orion Nebula (Figure 1) required use drites. Meteorites from unmelted bodies are called chon- of the Hubble Space Telescope (McCaughrean & O’Dell drites, because they contain chondrules, in addition to 1996), and each of the methods used to obtain the needed calcium-rich, aluminum-rich inclusions (CAIs), and micron- data faces limitations. Surveys (Haisch et al. 2001) suggest sized matrix grains. Each component provides useful con- typical disk lifetimes of 3 to 6 Myr, but these observations straints on events in the solar nebula. of infrared excesses do not probe the disk more than 1

8 Figure 2: Thin section of a chondrule from the CV3 chondrite NWA 6207, seen through a petrographic mi- Figure 1: Silhouetted protoplanetary disk in the Orion croscope, illuminated by cross-polarized light, revealing Nebula seen with the Hubble Space Telescope (McCaugh- a porphyritic igneous texture: hundreds of crystals that rean & O’Dell 1996). Data such as midplane density and grew relatively slowly from a melt. This chondrule also temperature at 1 AU are difficult to obtain from such im- contains large relict grains that are fragments of previously ages. Scale is about 1000 AU across. created chondrules with other textures. Scale is about 1 millimeter across. (http://meteorite-times.com/micro- visions/seeing-processing-in-a-cv3) CAIs are typically large, up to centimeter-sized, and composed of refractory minerals predicted to condense first low 650 K, so chondrules formed in a region of the disk from a cooling solar-composition gas. They are believed cooler than this. The majority ( 85% in ordinary chon- to be the first solids formed in the solar system. At the drites) of chondrules have porphyritic≈ textures (depicted time of their formation, they contained abundant 26Al, a in Figure 1), with hundreds of well-shaped crystals. This short-lived radionuclide with a half life of 0.7 Myr. Ma- requires that chondrules reached peak temperatures suffi- trix grains contain a mix of condensates as well as frag- cient to melt most but not all seed nuclei, and then cooled ments of chondrules and CAIs. Chondrules (see reviews slowly enough for crystals to form. Experiments, in which by Connolly & Desch 2004, Desch et al. 2005, 2010) are artificial chondrules are melted in furnaces, indicate that typically a few hundred microns to a millimeter in diam- peak temperatures 1750 2100 K are needed, and that eter, contained live 26Al when they formed (but not as chondrules must cool≈ at rates− 10 1000Khr−1 through much as CAIs), are composed of ferromagnesian (Fe- and the crystallization temperatures∼ −1400 1800K. The Mg-bearing) silicates. They also have igneous textures, cooling rate from the peak itself≈ may have− been faster: meaning they contain crystals whose sizes and shapes in- volatile species like K, Na and S should have been lost dicate that chondrules crystallized from a melt (Figure 2). within minutes from a fully molten chondrules; since chon- This was recognized as long ago as 1877 when Sorby called drules retain these, cooling rates from the peak 104 K hr−1 them “drops of fiery rain”. What melted the chondrules are inferred. Likewise, the heating of chondrules∼ must is a central mystery in meteoritics. In a typical chondrite, have been rapid, only minutes. Even during the crystal- chondrules make up 50-80% of the mass, and the aster- lization stage, retention of volatiles requires a high partial oid belt contains at least 1024 g of chondrules (Desch et pressure of these species in the gas, which in turn places al. 2012). Meteoriticists have long presented ideas about constraints (Cuzzi & Alexander 2006) on the density of what could have melted that much rock, but quantitative chondrules ( 10−5 cm−3) and the size of the region over models and rigorous tests require astrophysical modeling. which chondrules∼ were melted (> 103 km). It also requires −3 A successful astrophysical model of chondrule formation high pressures, > 10 bar. Alexander et al. (2008) have argued for a partial pressure 10−3 bar of Na vapor alone. must explain the following, detailed information about ∼ chondrules (see review by Desch et al. 2012 for references). It is known that 5% of chondrules are compound, stuck Chondrules contain primary S, which only condenses be- to another chondrule while both were plastic. This also

9 argues for a number density of chondrules 10−5 cm−3. ( 105 km in lateral extent), this typically requires dis- From radiometric dating using 26Al, we know∼ that most tances≫ > 105 km, taking many hours. During this interval, chondrules in our collections formed over a range of times chondrules (and the gas) cool at rates of tens of K per 2 to 3 Myr after CAIs. Chondrules often contain frag- hour. For a shock with lateral extent < 104 km, cooling is ments of previously formed chondrules (Figure 2). Chon- much more rapid, typically at 1000 3000Khr−1 (Bo- drules and matrix grains often appear chemically comple- ley et al. 2013; Morris et al. 2012).∼ In− the same region in mentary, meaning that matrix grains are enriched in some which chondrules form, micron-sized mineral grains can elements, and chondrules depleted in the same elements condense from the gas. Eventually the chondrules and (compared to a solar composition). This strongly sug- condensed grains cool and mix with other nebular mate- gests chondrules and matrix grains formed from the same rials that have not been heated by the shock. batch of solar-composition material, implying that chon- The timescales and thermal histories above assume a gas drules formed locally, about 2 to 3 AU from the Sun in −9 −3 density ρg 10 g cm , and a chondrule-to-gas mass ra- the protoplanetary disk. Astrophysical models of chon- tio 0.04.∼ With these parameters, all aspects of the ther- drule formation are constrained by a remarkable wealth of mal≈ histories of chondrules in solar nebula shocks match data about chondrules. the meteoritic constraints. These parameters are also consistent with the other constraints, such as the chondrule 3 Melting of chondrules by shocks density implied from the compound chondrule frequency. These are plausible parameters: at a few AU, the mini- To date, the model that most successfully explains these mum mass solar nebula model of Weidenschilling (1977) data is the nebular shock model (Connolly & Love 1998; predicts ρ 10−10 g cm−3, so these densities require a g ∼ Iida et al. 2001; Desch & Connolly 2002; Ciesla & Hood disk mass 0.1 M⊙, but this is not unreasonable (Desch 2002; Morris & Desch 2010; Morris et al. 2012; Boley et 2007). A moderate∼ but reasonable amount of gravitational al. 2013), in which chondrules were melted as they passed settling of chondrules to the disk midplane is also implied. through a shock wave in the gas of the protoplanetary disk. The other meteoritic constraints also can be met by the Critiques of alternative models were provided by Desch et shock model, provided that shocks 8kms−1 can be gen- al. (2010, 2012). Many (lightning, X winds) simply do not erated, repeatably, over many Myr.≈ Shocks must act at match the data. Other models (asteroid impacts) might the midplane of the 2-3 AU region of the disk. Large be applicable to some chondrules, but have not been quan- shocks (lateral extent 105 km) more easily meet the titatively developed enough to be tested. The shock wave constraints on cooling≫ rates, but smaller shocks ( 103 model has been fully developed, taking into account the km) may also comply. ∼ separate hydrodynamics of gas and particles, dissociation of H2 molecules, radiative transfer through dust and chondrules, etc., into detailed numerical codes. The shock wave 4 Shocks in protoplanetary disks model makes several quantitative predictions that match what is known about chondrules. Meteoritic data, coupled with numerical modeling of chondrule formation, point to two sources of shocks: large “spi- The shock wave melts chondrules through the following ral” shocks in the solar nebula, driven by gravitational sequence of events (Desch & Connolly 2002, Desch et al. instabilities (Wood 1984; Boss & Durisen 2005; Boley & 2005; Morris & Desch 2010). As the shock wave advances Durisen 2008); or bow shocks around large planetary bod- toward a region in the nebula at speeds 7 to 8kms−1, ≈ ies on eccentric orbits (Hood 1998; Weidenschilling 1998; chondrule precursors (clumps of dust, previous chondrule Ciesla et al. 2004; Morris et al. 2012; Boley et al. 2013). fragments, and possibly C or ice) are heated by the in- Shocks driven by gravitational instabilities are large, with frared radiation emitted by solids already heated behind lateral extent 106 km. Figure 3 illustrates how gravita- the shock. The precursors are already partially liquid tional instabilities≫ may manifest themselves in disks and by the time the shock itself arrives, at which point the create shocks. Bow shocks capable of melting chondrules chondrule is immersed in gas streaming past it at about 3 −1 would arise around planetary embryos several 10 km 6kms . The friction of the streaming gas accelerates the in radius, if they are driven into orbital resonances× so chondrules within 1 minute, during which time chondrules that they acquire orbits with high eccentricity (> 0.3 or are considerably heated. During this ﬁrst minute, chon- 4 −1 more). Figure 4 shows the gas temperatures surrounding drules cool several hundred K, at a rate 10 K hr . −1 ∼ such a body moving with speed 8kms with respect to After this, chondrules are immersed in the hot (> 2000 the gas in Keplerian rotation. Chondrules in gravitational K), compressed gas behind the shock. The gas and chon- instability-driven shocks cool more slowly, easily match- drules form a thermally coupled system, and both compo- ing the meteoritic constraints, while chondrules melted in nents cool only as fast as they can travel several optical bow shocks tend to cool at rates > 103 K hr−1, consis- depths away from the shock front. For a large-scale shock

10 Either model has profound implications for protoplanetary disks. Gravitational instabilities require massive disks, 0.1 M⊙, as do the thermal constraints. While not im- ∼plausible, the majority of disks weighed by measuring their millimeter ﬂuxes have lower masses, 0.005 M⊙ (Eisner & Carpenter 2006). The planetary bow∼ shock model requires planetary embryos to form before the time of chondrule formation, < 2 Myr after CAIs. Chondrules would not represent the building blocks of planets, but rather the crumbs left over after planet formation. Importantly, a substantial fraction of the solids mass in protoplanetary disks, even young disks < 2 Myr in age, must be locked in planets and hidden from millimeter observations. The masses of protoplanetary disks are very likely grossly un- derestimated by astronomical observations. This is just one of the many insights gained by leveraging chondrules and meteoritic data and using microscopes, not telescopes, to observe a protoplanetary disk. References: Figure 3: False color representation of the midplane den- Alexander, C. M. O.’D., Grossman, J. N., Ebel, D. S. & Ciesla, F. sities in the gravitationally unstable disk model of Boss & J. 2008, Science 320, 1617. Durisen (2005). Region shown is 20 AU in radius, and a Boley, A. C. & Durisen, R. H. 2008, ApJ 685, 1193. 1 M⊙ protostar lies at the center of the disk, whose inner Boley, A. C., Morris, M. A. & Desch, S. J. 2013, ApJ 776, 101. boundary is 2 AU in radius. A strong shock between very Boss, A. P. & Durisen, R. H. 2005, ApJ 621, L137. low-density material (black) and moderate- density mate- Bouvier, A. & Wadhwa, M. 2010, Nature Geoscience 3, 637. rial (purple) is seen at the 12 o’clock position, extending Ciesla, F. J. & Hood, L. L. 2002, Icarus 158, 281. from 2 AU to about 4 AU in radius. Ciesla, F. J., Hood, L. L. & Weidenschilling, S. J. 2004, Icarus 158, 281. Connolly, Jr., H. C. & Desch, S. J. 2004, Chemie der Erde 64, 95. Connolly, Jr., H. C. & Love, S. G. 1998, Science, 280, 62. Cuzzi, J. N. & Alexander, C. M. O’D. 1996, Nature 441, 483. Desch, S. J. 2007, ApJ 671, 878. Desch, S. J. & Connolly, Jr., H. C. 2002, Meteorit. and Planet. Sci. 37, 183. Desch, S. J., Ciesla, F. J., Hood, L. L. & Nakamoto, T. 2005, in Chondrites and the Protoplanetary Disk, eds. A. Krot, E. R. D. Scott and B. Reipurth, Astronomical Society of the Paciﬁc Confer- ence Series 341, 849. Desch, S. J., Morris, M. A., Connolly, Jr., H. C. & Boss, A. P. 2010, Figure 4: Temperatures of gas in the bow shock region ApJ 725, 692. − around a planetary embryo moving at 8 km s 1 to the Desch, S. J., Morris, M. A., Connolly, Jr., H. C. & Boss, A. P. 2012, right, as calculated by Boley et al. (2013). The trajecto- Meteorit. and Planet. Sci. 47, 1139. ries of chondrule precursors and chondrules are shown in Eisner, J. A. & Carpenter, J. M. 2006, ApJ 641, 1162. blue (moving from right to left with respect to the body). Haisch, Jr., K. E., Lada, E. A. & Lada, C. J. 2001, ApJL 553, L153. Iida, A., Nakamoto, T., Susa, H. & Nakagawa, Y. 2001, Icarus 153, 430. tent with the constraints but just barely. On the other McCaughrean, M. J. & O’Dell, R. C. 1996, AJ 111, 1977. hand, passage of chondrules through the atmospheres of these bodies may explain the high Na vapor pressures dur- Morris, M. A. & Desch, S. J. 2010, ApJ 722, 1474. ing chondrule formation, something impossible to explain Morris, M. A., Boley, A. C., Desch, S. J. & Athanassiadou, T. 2012, using nebular shocks. Further investigations will reveal ApJ 752, 27. which type of shock melted chondrules. Of course, both Weidenschilling, S. J. 1977, Ap&SS 51, 153. may have: the two models are not exclusive. Wood, J. A. 1984, Meteoritics 19, 339.

11 Abstracts of recently accepted papers

Distributions of Short-Lived Radioactive Nuclei Produced by Young Embedded Star Clusters Fred C. Adams1, Marco Fatuzzo2 and Lisa Holden3 1 University of Michigan, USA 2 Xavier University, USA 3 Northern Kentucky University, USA E-mail contact: fca at umich.edu Most star formation in the Galaxy takes place in clusters, where the most massive members can affect the properties of other constituent solar systems. This paper considers how clusters influence star formation and forming planetary systems through nuclear enrichment from supernova explosions, where massive stars deliver short-lived radioactive nuclei (SLRs) to their local environment. The decay of these nuclei leads to both heating and ionization, and thereby affects disk evolution, disk chemistry, and the accompanying process of planet formation. Nuclear enrichment can take place on two spatial scales: [1] Within the cluster itself (ℓ 1pc), the SLRs are delivered to the circumstellar disks associated with other cluster members. [2] On the next larger∼ scale (ℓ 2 10pc), SLRs are injected into the background molecular cloud; these nuclei provide heating and ionization to∼ nearby− star-forming regions, and to the next generation of disks. For the first scenario, we construct the expected distributions of radioactive enrichment levels provided by embedded clusters. Clusters can account for the SLR mass fractions inferred for the early Solar Nebula, but typical SLR abundances are lower by a factor of 10. For the second scenario, we find that distributed enrichment of SLRs in molecular clouds leads to comparable abundances.∼ For both the direct and distributed enrichment processes, 26 60 the masses of Al and Fe delivered to individual circumstellar disks typically fall in the range 10 100pM⊙ (where −12 − −19 1pM⊙ = 10 M⊙). The corresponding ionization rate due to SLRs typically falls in the range ζSLR 1 5 10 −1 −17 −1 ∼ − × sec . This ionization rate is smaller than that due to cosmic rays, ζCR 10 sec , but will be important in regions where cosmic rays are attenuated (e.g., disk mid-planes). ∼ Accepted by The Astrophysical Journal http://arXiv.org/pdf/1405.5142

Herschel’s view of the large-scale structure in the Chamaeleon dark clouds C. Alves de Oliveira1, N. Schneider2,3, B. Mer´ın1, T. Prusti4, A.´ Ribas1,5,6, N. L. J. Cox7, R. Vavrek1, V. Könyves8,9, D. Arzoumanian9, E. Puga1,10, G. L. Pilbratt4, A.´ Kóspál4, Ph. André8, P. Didelon8, A. Men’shchikov8, P. Royer7, C. Waelkens7, S. Bontemps2,3, E. Winston4 and L. Spezzi11 1 European Space Agency (ESA/ESAC, SRE-O), P.O. Box 78, 28691 Villanueva de la Cañada (Madrid), Spain 2 Universitéde Bordeaux, Laboratoire d’Astrophysique de Bordeaux, CNRS/INSU, 33270 Floirac, France 3 CNRS, LAB, UMR 5804, 33270, Floirac, France 4 European Space Agency (ESA/ESTEC, SRE-S), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands 5 Ingenier´ıay Servicios Aeroespaciales, European Space Agency (ESA/ESAC, SRE-O), P.O. Box 78, 28691 Villanueva de la Cañada (Madrid), Spain 6 Centro de Astrobiologia (INTA-CSIC), P.O. Box 78, 28691 Villanueva de la Cañada (Madrid), Spain 7 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, bus 2401, 3001 Leuven, Belgium 8 Laboratoire AIM, CEA/DSM-CNRS-UniversitéParis Diderot, IRFU/SAp, CEA Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, France 9 IAS, CNRS (UMR 8617), UniversitéParis-Sud 11, Bâtiment 121, 91400 Orsay, France 10 Vega, European Space Agency (ESA/ESAC, SRE-O), P.O. Box 78, 28691, Villanueva de la Cañada (Madrid), Spain 11 European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany

12 E-mail contact: calves at sciops.esa.int Context. The Chamaeleon molecular cloud complex is one of the nearest star-forming sites encompassing three molecular clouds (Cha I, II, and III) with a different star-formation history, from quiescent (Cha III) to actively forming stars (Cha II), and reaching the end of star-formation (Cha I). Aims. We aim at characterising the large-scale structure of the three sub-regions of the Chamaeleon molecular cloud complex by analysing new far-infrared images taken with the Herschel Space Observatory. Methods. We derived column density and temperature maps using PACS and SPIRE observations from the Herschel Gould Belt Survey, and applied several tools, such as filament tracing, power-spectra, ∆-variance, and probability distribution functions of column density (PDFs), to derive physical properties. Results. The column density maps reveal a different morphological appearance for the three clouds, with a ridge- like structure for Cha I, a clump-dominated regime for Cha II, and an intricate filamentary network for Cha III. The filament width is measured to be around 0.12 0.04 pc in the three clouds, and the filaments found to be gravitationally unstable in Cha I and II, but mostly subcritical± in Cha III. Faint filaments (striations) are prominent in Cha I showing a preferred alignment with the large-scale magnetic field. The PDFs of all regions show a lognormal distribution at low column densities. For higher densities, the PDF of Cha I shows a turnover indicative of an extended higher density component, culminating with a power-law tail. Cha II shows a power-law tail with a slope characteristic of gravity. The PDF of Cha III can be best fit by a single lognormal. Conclusions. The turbulence properties of the three regions are found to be similar, pointing towards a scenario where the clouds are impacted by large-scale processes. The magnetic field could possibly play an important role for the star-formation efficiency in the Chamaeleon clouds if proven that it can effectively channel material on Cha I, and possibly Cha II, but probably less efficiently on the quiescent Cha III cloud. Accepted by A&A http://arxiv.org/pdf/1404.6526

Recent outburst of the young star V1180 Cas S. Antoniucci1, A. A. Arkharov2, A. Di Paola1, T. Giannini1, A. Harutyunyan3, E. N. Kopatskaya4, V. M. Larionov2,4, G. Li Causi1,5, D. Morozova4, B. Nisini1 and F. Vitali1 1 INAF-Osservatorio Astronomico di Roma, Via Frascati 33, Monte Porzio Catone (RM), Italy 2 Central Astronomical Observatory of Pulkovo, Pulkovskoe shosse 65, 196140 St. Petersburg, Russia 3 Fundacion Galileo Galilei - INAF, Telescopio Nazionale Galileo, 38700 Santa Cruz de la Palma, Tenerife, Spain 4 Astronomical Institute of St. Petersburg University, Russia 5 INAF-Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, 00133 Roma, Italy E-mail contact: simone.antoniucci at oa-roma.inaf.it We report on the ongoing outburst of the young variable V1180 Cas, which is known to display characteristics in common with EXor eruptive variables. We present results that support the scenario of an accretion-driven nature of the brightness variations of the object and provide the first evidence of jet structures around the source. We monitored the recent flux variations of the target in the RC , J, H, and K bands. New optical and near-IR spectra taken during the current high state of V1180 Cas are presented, in conjunction with H2 narrow-band imaging of the source. Observed near-IR colour variations are analogous to those observed in EXors and consistent with excess emission originating from an accretion event. The spectra show numerous emission lines, which indicates accretion, ejection of matter, and an active disc. Using optical and near-IR emission features we derive a mass accretion rate of −8 −1 3 10 M⊙ yr , which is an order of magnitude lower than previous estimates. In addition, a mass loss rate of ∼ × −9 −10 −1 4 10 and 4 10 M⊙ yr are estimated from atomic forbidden lines and H2, respectively. Our H2 imaging reveals∼ × two bright∼ knots× of emission around the source and the nearby optically invisible star V1180 Cas B, clearly indicative of mass-loss phenomena. Higher resolution observations of the detected jet will help to clarify whether V1180 Cas is the driving source and to determine the relation between the observed knots. Accepted by A&A http://arxiv.org/pdf/1405.0612

13 HD100546 Multi-Epoch Scattered-Light Observations Henning Avenhaus1, Sascha P. Quanz1, Michael R. Meyer1, Sean D. Brittain2, John S. Carr3 and Joan R. Najita4 1 ETH Zurich, Institute for Astronomy, Wolfgang-Pauli- Strasse 27, 8093 Zurich, Switzerland 2 Department of Physics & Astronomy, 118 Kinard Labora- tory, Clemson University, Clemson, SC 29634, USA 3 Naval Research Laboratory, Code 7211, Washington, DC 20375, USA 4 National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719, USA E-mail contact: havenhaus at phys.ethz.ch ′ We present H, Ks and L filter polarimetric differential imaging (PDI) data for the transitional disk around HD100546 obtained in 2013, together with an improved re-reduction of previously published 2006 data. We reveal the disk in polarized scattered light in all three filters, achieving an inner working angle of 0.1 arcsec. Additional, short-exposure ∼ observations in the H and Ks filter probe the surrounding of the star down to 0.03 arcsec ( 3 AU). HD100546 is fascinating because of its variety of sub-structures possibly related to forming planets∼ in the disk,∼ and PDI is currently the best technique to image them in the near-IR. Our key results are: (1) For the first time ever, we detect a disk in L-band PDI data. (2) We constrain the outer radius of the inner hole to 14 2 AU and its eccentricity to < 0.133. (3) We detect a dark lane between 0.2-0.6 arcsec AU in the front side of the± disk, which is likely an effect of the scattering angle and the scattering∼ function of the grains. (4) We find a spiral arm in the northeast which has no obvious connection to spiral arms seen before by other authors further out in the disk, but winds in the same direction (clockwise). (5) The two bright scattering peaks along the semi-major axis are asymmetric, with the southeastern one being significantly brighter. This could be related to the inner companion candidate that is close to the brighter side of the disk at the time of the observations. (6) The scattering color is close to grey between H and Ks filter ([H]-[Ks] ′ ′ ′ = 0.19 0.11), but the scattering in L filter is significantly weaker ([H]-[L ] = -1.08 0.35, [Ks]-[L ] = -1.27 0.35). (7) We± measure the position angle of the disk to be 138◦ 3◦, consistent with previous± observations. (8) We± derive ± ◦ ◦ the dust scattering function in the H and Ks filter between 35 and 130 at two different radii (30-50 and 80-110 AU) and show that our results are consistent with a disk that∼ is more ∼strongly flared in the outer regions. Accepted by ApJ http://arxiv.org/pdf/1405.6120

The statistical properties of stars and their dependence on metallicity: the effects of opacity Matthew R. Bate1 1 School of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom E-mail contact: mbate at astro.ex.ac.uk We report the statistical properties of stars and brown dwarfs obtained from four radiation hydrodynamical simulations of star cluster formation that resolve masses down to the opacity limit for fragmentation. The calculations are identical except for their dust and gas opacities. Assuming dust opacity is proportional to metallicity, the calculations span a range of metallicities from 1/100 to 3 times solar, although we emphasise that changing the metallicity has other thermodynamic effects that the calculations do not capture (e.g. on the thermal coupling between gas and dust). All four calculations produce stellar populations whose statistical properties are difficult to distinguish from observed stellar systems, and we find no significant dependence of stellar properties on opacity. The mass functions and properties of multiple stellar systems are consistent with each other. However, we find protostellar mergers are more common with lower opacities. Combining the results from the three calculations with the highest opacities, we obtain a stellar population consisting of more than 500 stars and brown dwarfs. Many of the statistical properties of this population are in good agreement with those observed in our Galaxy, implying that gravity, hydrodynamics, and radiative feedback may be the primary ingredients for determining the statistical properties of low-mass stars. However, we do find indications that the calculations may be slightly too dissipative. Although further calculations will be required to understand all of the effects of metallicity on stellar properties, we conclude that stellar properties are surprisingly resilient to variations of the dust and gas opacities. Accepted by MNRAS

14 Preprint at: http://arxiv.org/pdf/1405.5583 Animations available at: http://www.astro.ex.ac.uk/people/mbate/Research/Cluster/clusterMetallicity.html Dataset available at: http://hdl.handle.net/10871/14881

The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark Cloud Cara Battersby1,2, Adam Ginsburg2,3, John Bally2, Steve Longmore4, Miranda Dunham5, and Jeremy Darling2 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA 2 Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309, USA 3 European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Munchen, Germany 4 Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK 5 Department of Astronomy, Yale University, New Haven, CT 06520, USA E-mail contact: cbattersby at cfa.harvard.edu

We present new NH3 (1,1), (2,2), and (4,4) observations from the Karl G. Jansky Very Large Array (VLA) compiled with work in the literature to explore the range of conditions observed in young, massive star-forming regions. To sample the effects of evolution independent from those of distance/resolution, abundance, and large-scale environment, we compare clumps in different evolutionary stages within a single Infrared Dark Cloud (IRDC), G32.02+0.06. We find that the early stages of clustered star formation are characterized by dense, parsec-scale filamentary structures interspersed with complexes of dense cores (<0.1 pc cores clustered in complexes separated by 1 pc) with masses from ∼ about 10 to 100 M⊙. The most quiescent core is the most extended while the star forming cores are denser and more compact, showing very similar column density structure before and shortly after the onset of massive star formation, with peak surface densities Σ > 1 g cm−2. Quiescent cores and filaments show smoothly varying temperatures from 10-20 K, rising to over 40 K in∼ star-forming cores. We calculate virial parameters for 16 cores and find that the level of support provided by turbulence is generally insufficient to support them against gravitational collapse ( αvir 0.6). The star-forming filaments show smooth velocity fields, punctuated by discontinuities at the sites of activeh stari ∼ 5 formation. We discuss the Massive Molecular Filament (MMF; M 10 M⊙, length > 60 pc) hosting the IRDC, hypothesizing that it may have been shaped by previous generations∼ of massive stars Accepted by ApJ http://arxiv.org/pdf/1405.3286 http://adsabs.harvard.edu/abs/2014ApJ...787..113B

The Comparison of Physical Properties Derived from Gas and Dust in a Massive Star- forming Region Cara Battersby1,2, John Bally1, Miranda Dunham3, Adam Ginsburg1,4,3, , Steve Longmore5, and Jeremy Darling1 1 Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309, USA 2 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA 3 Department of Astronomy, Yale University, New Haven, CT 06520, USA 4 European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Munchen, Germany 5 Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK E-mail contact: cbattersby at cfa.harvard.edu We explore the relationship between gas and dust in massive star-forming regions by comparing the physical properties derived from each. We compare the temperatures and column densities in a massive star-forming Infrared Dark Cloud (IRDC, G32.02+0.05), which shows a range of evolutionary states, from quiescent to active. The gas properties were derived using radiative transfer modeling of the (1,1), (2,2), and (4,4) transitions of NH3 on the Karl G. Jansky Very Large Array (VLA), while the dust temperatures and column densities were calculated using cirrus-subtracted,

15 modified blackbody fits to Herschel data. We compare the derived column densities to calculate an NH3 abundance, −8 χNH = 4.6 10 . In the coldest star-forming region, we find that the measured dust temperatures are lower than 3 × the measured gas temperatures (mean and standard deviations Tdust,avg 11.6 0.2 K vs. Tgas,avg 15.2 1.5 K), which may indicate that the gas and dust are not well-coupled in the∼ youngest± regions ( 0.5 Myr)∼ or that± these observations probe a regime where the dust and/or gas temperature measurements are unreliable.∼ Finally, we calculate millimeter fluxes based on the temperatures and column densities derived from NH3 which suggest that millimeter dust continuum observations of massive star-forming regions, such as the Bolocam Galactic Plane Survey or ATLASGAL, can probe hot cores, cold cores, and the dense gas lanes from which they form, and are generally not dominated by the hottest core. Accepted by ApJ http://arXiv.org/pdf/1405.3308 http://adsabs.harvard.edu/abs/2014ApJ...786..116B

An Observational Method to Measure the Relative Fractions of Solenoidal and Com- pressible Modes in Interstellar Clouds C.M. Brunt1 and C. Federrath2,3 1 Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK 2 Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Vic 3800, Australia 3 Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Uerberle-Str. 2, 69120 Heidelberg, Germany E-mail contact: brunt at astro.ex.ac.uk We introduce a new method for observationally estimating the fraction of momentum density (ρv) power contained in solenoidal modes (for which ρv = 0) in molecular clouds. The method is successfully tested with numerical simulations of supersonic turbulence∇ · that produce the full range of possible solenoidal/compressible fractions. At present the method assumes statistical isotropy, and does not account for anisotropies caused by (e.g.) magnetic fields. We also introduce a framework for statistically describing density–velocity correlations in turbulent clouds. Accepted by MNRAS http://arxiv.org/pdf/1405.1285

Imaging the disk around IRAS20126+4104 at subarcsecond resolution R. Cesaroni1, D. Galli1, R. Neri2 and C.M. Walmsley1,3 1 INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy 2 IRAM, 300 rue de la Piscine, 38406, Saint Martin d’Heres, France 3 Dublin Institute for Advanced Studies (DIAS), 31 Fitzwilliam Place, Dublin 2, Ireland E-mail contact: cesa at arcetri.astro.it The existence of disks around high-mass stars has yet to be established on a solid ground, as only few reliable 4 candidates are known to date. The disk rotating about the 10 L⊙ protostar IRAS20126+4104 is probably the most convincing of these. We would like to resolve the disk structure∼ in IRAS20126+4104 and, if possible, investigate the relationship between the disk and the associated jet emitted along the rotation axis. We performed observations at 1.4 mm with the IRAM Plateau de Bure interferometer attaining an angular resolution of 0.4′′ ( 660 AU). We ∼ ∼ 13 imaged the methyl cyanide J=12 11 ground state and vibrationally excited transitions as well as the CH3 CN isotopologue, which had proved to→ be disk tracers. Our findings confirm the existence of a disk rotating about a 7–10 M⊙ star in IRAS20126+4104, with rotation velocity increasing at small radii. The dramatic improvement in sensitivity∼ and spectral and angular resolution with respect to previous observations allows us to establish that higher excitation transitions are emitted closer to the protostar than the ground state lines, which demonstrates that the gas temperature is increasing towards the centre. We also find that the material is asymmetrically distributed in the disk and speculate on the possible origin of such a distribution. Finally, we demonstrate that the jet emitted along the disk axis is co-rotating with the disk. We present iron-clad evidence of the existence of a disk undergoing rotation around a B-type protostar, with rotation velocity increasing towards the centre. We also demonstrate that the disk

16 is not axially symmetric. These results prove that B-type stars may form through disk-mediated accretion as their low-mass siblings do, but also show that the disk structure may be signiﬁcantly perturbed by tidal interactions with (unseen) companions, even in a relatively poor cluster such as that associated with IRAS20126+4104. Accepted by A&A http://www.arcetri.astro.it/science/starform/preprints/cesa_24.pdf

Study of background star polarization and polarization efficiency of three selected Bok globules CB56, CB60 and CB69 A. Chakraborty1, H.S. Das1, and D. Paul2 1 Department of Physics, Assam University, Silchar 788011, India 2 Department of Physics, Ramkrishna Nagar College, Ramkrishna Nagar 788166, India E-mail contact: hsdas at iucaa.ernet.in We present the polarization maps of three selected Bok globules CB56, CB60 and CB69 constructed using a V-band data from a CCD imaging polarimeter. The aim of this work is to measure the optical polarization (pv) of background field stars in order to determine the polarization efficiency, pv/Av. We find that the local magnetic field of the cloud CB56 is almost aligned with the galactic field, but not in CB60 and CB69. A trend of decreasing polarization −α efficiency with increasing extinction (Av) is observed: it can be well represented by a power law, pv/Av Av , where α = 0.56 0.36, 0.59 0.51 and 0.52 0.49 for CB56, CB60 and CB69 respectively. This indicates that∝ the linear polarization− ± of the− starlight± due to− aligned± dust grains in these clouds is produced more efficiently in low extinction regions, compared with high obscured lines of sight. Accepted by MNRAS http://arxiv.org/pdf/1405.6269

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits: II- Survey description, results and performances G. Chauvin1, A. Vigan2, M. Bonnefoy3, S. Desidera4, M. Bonavita4, D. Mesa4, A. Boccaletti5, E. Buenzli3, J. Carson6,3, P. Delorme1, J. Hagelberg7, G. Montagnier2, C. Mordasini3, S.P. Quanz8, D. Segransan7, C. Thalmann8, J.-L. Beuzit1, B. Biller3, E. Covino9, M. Feldt3, J. Girard10, R. Gratton4, T. Henning3, M. Kasper11, A.-M. Lagrange1, S. Messina12, M. Meyer8, D. Mouillet1, C. Moutou2,M. Reggianni8, J.E. Schlieder3, and A. Zurlo2 1 UJF-Grenoble1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble UMR 5274, Grenoble, F- 38041, France 2 Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France 3 Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany 4 INAF - Osservatorio Astronomico di Padova, Vicolo dell Osservatorio 5, 35122, Padova, Italy 5 LESIA, Observatoire de Paris Meudon, 5 pl. J. Janssen, 92195 Meudon, France 6 Department of Physics & Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424, USA 7 Geneva Observatory, University of Geneva, Chemin des Mailettes 51, 1290 Versoix, Switzerland 8 Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland 9 INAF Osservatorio Astronomico di Capodimonte Via Moiarello 16 80131 Napoli Italy 10 European Southern Observatory, Casilla 19001, Santiago 19, Chile 11 European Southern Observatory, Karl Schwarzschild St, 2, D-85748 Garching, Germany 12 INAF - Catania Astrophysical Observatory, via S. So a 78 I-95123 Catania, Italy E-mail contact: gael.chauvin at obs.ujf-grenoble.fr In anticipation of the VLT/SPHERE planet imager guaranteed time programs, we have conducted a preparatory survey of 86 stars between 2009 and 2013 in order to identify new faint comoving companions to ultimately carry out a comprehensive analysis of the occurence of giant planets and brown dwarf companions at wide (10–2000 AU) orbits around young, solar-type stars. We used NaCo at VLT to explore the occurrence rate of giant planets and brown dwarfs

17 between typically 0.1 and 8′′. Diffraction-limited observations in H-band combined with angular differential imaging enabled us to reach primary star-companion brightness ratios as small as 10−6 at 1′′. 5. 12 systems were resolved as new binaries, including the discovery of a new white dwarf companion to the star HD8049. Around 34 stars, at least one companion candidate was detected in the observed field of view. More than 400 faint sources were detected, 90% of them in 4 crowded fields. With the exception of HD 8049 B, we did not identify any new comoving companions. The survey also led to spatially resolved images of the thin debris disk around HD 61005 that have been published earlier. Finally, considering the survey detection limits, we derive a preliminary upper limit on the frequency of giant planets for semi-major axes of [10,2000] AU: typically less than 15% between 100 and 500 AU, and less than 10% between 50 and 500 AU for exoplanets more massive than 5 MJup and 10 MJup respectively, considering a uniform input distribution and with a confidence level of 95%. Accepted by A&A http://arxiv.org/pdf/1405.1560

Near Infrared Spectroscopy of Young Brown Dwarfs in Upper Scorpius P. Dawson1, A. Scholz2, T.P. Ray1, D.E. Peterson3, D. Rodgers-Lee1, V. Geers1 1 School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland 2 School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS, UK 3 Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA E-mail contact: pdawson at cp.dias.ie Spectroscopic follow-up is a pre-requisite for studies of the formation and early evolution of brown dwarfs. Here we present IRTF/SpeX near-infrared spectroscopy of 30 candidate members of the young Upper Scorpius association, selected from our previous survey work. All 24 high confidence members are confirmed as young very low mass objects with spectral types from M5 to L1, 15–20 of them are likely brown dwarfs. This high yield confirms that brown dwarfs in Upper Scorpius can be identified from photometry and proper motions alone, with negligible contamination from field objects (<4%). Out of the 6 candidates with lower confidence, 5 might still be young very low mass members of Upper Scorpius, according to our spectroscopy. We demonstrate that some very low mass class II objects exhibit radically different near infrared (0.6–2.5 µm) spectra from class III objects, with strong excess emission increasing towards longer wavelengths and partially filled in features at wavelengths shorter than 1.25 µm. These characteristics can obscure the contribution of the photosphere within such spectra. Therefore, we caution that near infrared derived spectral types for objects with discs may be unreliable. Furthermore, we show that the same characteristics can be seen to some extent in all class II and even a significant fraction of class III objects ( 40%), indicating that some of them are still surrounded by traces of dust and gas. Based on our spectra, we select a∼ sample of objects with spectral types of M5 to L1, whose near-infrared emission represents the photosphere only. We recommend the use of these objects as spectroscopic templates for young brown dwarfs in the future. Accepted by MNRAS http://arxiv.org/pdf/1405.3842

The VLT/NaCo Large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits: I- Sample definition and characterization S. Desidera1, E. Covino2, S. Messina3, J. Carson4,5, J. Hagelberg6, J.E. Schlieder5, K. Biazzo3, J.M. Alcalá2, G. Chauvin7, A. Vigan8, J.L. Beuzit7, M. Bonavita1, M. Bonnefoy5, P. Delorme7, V. D’Orazi9,1, M. Esposito10,2, M. Feldt5, L. Girardi1, R. Gratton1, T. Henning5, A.M. Lagrange7, A.C. Lanzafame3,11, R. Launhardt5, M. Marmier6, C. Melo12, M. Meyer13, D. Mouillet7, C. Moutou8, D. Segransan6, S. Udry6, and C.M. Zaidi7 1 INAF-Osservatorio Astronomico di Padova, Vicolo dellOsservatorio 5, 35122 Padova, Italy 2 INAF-Osservatorio Astronomico di Napoli, Salita Moiariello 16, 80131, Napoli, Italy 3 INAF-Osservatorio Astrosico di Catania, Via S. Soa 78, 95123 Catania, Italy 4 Department of Physics & Astronomy, College of Charleston, 58 Coming St. Charleston, SC 29424, USA 5 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117, Heidelberg, Germany

18 6 Geneva Observatory, University of Geneva, Chemin des Mailettes 51, 1290 Versoix, Switzerland 7 Institut de Planétologie et dAstrophysique de Grenoble, UJF, CNRS, 414 rue de la piscine, 38400 Saint Martin d’Héres, France 8 Aix Marseille Universite, CNRS, LAM (Laboratoire dAstrophysique de Marseille) UMR 7326, 13388, Marseille, France 9 Department of Physics and Astronomy, Faculty of Science, Macquarie University, Sydney, NSW, 2109, Australia 10 Instituto de Astrosica de Canarias, C/ Via Lactea, s/n, E38205 - La Laguna (Tenerife), Spain 11 Universitádi Catania, Dipartimento di Fisica e Astronomia, Via S. Soa 78, 95123 Catania, Italy 12 European Southern Observatory, Casilla 19001, Santiago 19, Chile 13 Institute for Astronomy, ETH Zurich, Wolfgang-Pauli Strasse 27, 8093 Zurich, Switzerland E-mail contact: gael.chauvin at obs.ujf-grenoble.fr Young, nearby stars are ideal targets to search for planets using the direct imaging technique. The determination of stellar parameters is crucial for the interpretation of imaging survey results particularly since the luminosity of substellar objects has a strong dependence on system age. We have conducted a large program with NaCo at the VLT in order to search for planets and brown dwarfs in wide orbits around 86 stars. A large fraction of the targets observed with NaCo were poorly investigated in the literature. We performed a study to characterize the fundamental properties (age, distance, mass) of the stars in our sample. To improve target age determinations, we compiled and analyzed a complete set of age diagnostics. We measured spectroscopic parameters and age diagnostics using dedicated observations acquired with FEROS and CORALIE spectrographs at La Silla Observatory. We also made extensive use of archival spectroscopic data and results available in the literature. Additionally, we exploited photometric time- series, available in ASAS and Super-WASP archives, to derive rotation period for a large fraction of our program stars. We provided updated characterization of all the targets observed in the VLT NaCo Large program, a survey designed to probe the occurrence of exoplanets and brown dwarfs in wide orbits. The median distance and age of our program stars are 64 pc and 100 Myr, respectively. Nearly all the stars have masses between 0.70 and 1.50 M⊙, with a median value of 1.01 M⊙. The typical metallicity is close to solar, with a dispersion that is smaller than that of samples usually observed in radial velocity surveys. Several stars are confirmed or proposed here to be members of nearby young moving groups. Eight spectroscopic binaries are identified. Accepted by A&A http://arxiv.org/pdf/1405.1559

Structure and Dynamics of the Accretion Process and Wind in TW Hya A.K. Dupree1, N.S. Brickhouse1, S.R. Cranmer1, P. Berlind1,2, Jay Strader1,3, Graeme H. Smith4 1 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 2 Fred L. Whipple Observatory, Amado, AZ, USA 3 Michigan State University, East Lansing, MI, USA 4 University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064, USA E-mail contact: dupree at cfa.harvard.edu Time-domain spectroscopy of the classical accreting T Tauri star, TW Hya, covering a decade and spanning the far UV to the near-infrared spectral regions can identify the radiation sources, the atmospheric structure produced by accretion,and properties of the stellar wind. On time scales from days to years, substantial changes occur in emission line profiles and line strengths. Our extensive time-domain spectroscopy suggests that the broad near-IR, optical, and far-uv emission lines, centered on the star, originate in a turbulent post-shock region and can undergo scattering by the overlying stellar wind as well as some absorption from infalling material. Stable absorption features appear in Hα, apparently caused by an accreting column silhouetted in the stellar wind. Inflow of material onto the star is revealed by the near-IR He i 10830A line, and its free-fall velocity correlates inversely with the strength of the post-shock emission, consistent with a dipole accretion model. However, the predictions of hydrogen line profiles based on accretion stream models are not well-matched by these observations. Evidence of an accelerating warm to hot stellar wind is shown by the near-IR He i line, and emission profiles of C ii, C iii, C iv, N v, and O vi. The outflow of material changes substantially in both speed and opacity in the yearly sampling of the near-IR He i line over a decade. Terminal outflow velocities that range from 200 km s−1 to almost 400 km s−1 in He i appear to be directly related to the amount of post- shock emission, giving evidence for an accretion-driven stellar wind. Calculations of the emission from realistic

19 post- shock regions are needed. Accepted by ApJ http://arxiv.org/pdf/1405.2935

Deep VLA Images of the HH 124 IRS Radio Cluster and its Surroundings and a New Determination of the Distance to NGC 2264 Sergio A. Dzib1,2, Laurent Loinard1, Luis F. Rodriguez1,3 and Phillip Galli4 1 Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico. Apartado Postal 3-72, 58090, Morelia, Michoacan, Mexico. 2 Max-Planck-Institute fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn, Germany. 3 King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia 4 Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226 , Cidade Universitaria, 05508-900, Sao Paulo, SP, Brazil E-mail contact: sdzib at mpifr-bonn.mpg.de We present new deep (σ 6 µJy) radio images of the HH 124 IRS Radio Cluster at 4.8 and 7.5 GHz. We detect a total of 50 radio sources,∼ most of them compact. Variability and spectral indices were analyzed in order to determine the nature of the sources and of their radio emission. A proper motion study was also performed for several of these radio sources using radio observation previously reported. Our analysis shows that 11 radio sources can be related with Galactic objects, most of them probably young stars. Interestingly, eight of these sources are in an area less than 1 square arcminute in size. The importance of such compact clusters resides in that all its members can be observed in a single pointing with most telescopes, and are, therefore, ideal for multi-wavelength studies of variability. Another 4 of the detected sources are clearly extragalactic. Finally, we propose from statistical arguments that from the remaining sources, about 10 are Galactic, but our study does not allow us to identify which of the sources fall in that specific category. The relatively large proper motions observed for the sources in HH 124 IRS suggest that this region is located at about 400 pc from the Sun. This is significantly smaller than the 800–900 pc distance usually assigned to the nearby open cluster NGC 2264 with which HH 124 is thought to be associated.∼ However, a reanalysis of the Hipparcos parallaxes for members of NGC 2264, a convergent point approach, and a kinematic analysis all argue in favor of a distance of order 400 pc for NGC 2264 as well. Accepted by The Astrophysical Journal http://adsabs.harvard.edu/abs/2014arXiv1404.7543D

Dynamical star-disk interaction in the young stellar system V354 Mon N. N. J. Fonseca1,2,3, S. H. P. Alencar1, J. Bouvier2, F. Favata4 and E. Flaccomio5 1 Departamento de F´ısica - ICEx - UFMG, Av. Antônio Carlos, 6627, 31270-901, Belo Horizonte, MG, Brazil 2 UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Greno- ble, F-38041, France 3 CAPES Foundation, Ministry of Education of Brazil, Bras´ılia- DF 70040-020, Brazil 4 European Space Agency, 8-10 rue Mario Nikis, 75738 Paris Cedex 15, France 5 Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Palermo G.S. Vaiana, Piazza del Parlamento 1, 90134 Palermo, Italy E-mail contact: nath at fisica.ufmg.br The main goal of this work is to characterize the mass accretion and ejection processes of the classical T Tauri star V354 Mon, a member of the young stellar cluster NGC 2264. In March 2008, photometric and spectroscopic observations of V354 Mon were obtained simultaneously with the CoRoT satellite, the 60 cm telescope at the Observatório Pico dos Dias (LNA - Brazil) equipped with a CCD camera and Johnson/Cousins BV(RI)c filters, and the SOPHIE échelle spectrograph at the Observatoire de Haute-Provence (CNRS - France). The light curve of V354 Mon shows periodical minima (P = 5.26 0.50 days) that vary in depth and width at each rotational cycle. The BV(RI)c observations indicate that the± system becomes slightly bluer as the flux increases. The spectra of this T Tauri star exhibit variable emission lines, with blueshifted and redshifted absorption components associated with a disk wind

20 and with the accretion process, respectively, conﬁrming the magnetospheric accretion scenario. From the analysis of the photometric and spectroscopic data, it is possible to identify correlations between the emission line variability and the light-curve modulation of the young system, such as the occurrence of pronounced redshifted absorption in the Hα line at the epoch of minimum ﬂux. This is evidence that during photometric minima we see the accretion funnel projected onto the stellar photosphere in our line of sight, implying that the hot spot coincides with the light-curve minima. We applied models of cold and hot spots and a model of occultation by circumstellar material to investigate the source of the observed photometric variations. We conclude that nonuniformly distributed material in the inner part of the circumstellar disk is the main cause of the photometric modulation, which does not exclude the presence of hot and cold spots at the stellar surface. It is believed that the distortion in the inner part of the disk is created by the dynamical interaction between the stellar magnetosphere, inclined with respect to the rotation axis, and the circumstellar disk, as also observed in the classical T Tauri star AA Tau and predicted by magnetohydrodynamical numerical simulations. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1405.6988

A CGPS Look at the Spiral Structure of the Outer Milky Way I: Distances and Velocities to Star Forming Regions Tyler J. Foster1,2 and Christopher M. Brunt3 1 Department of Physics & Astronomy, Brandon University, Brandon, Manitoba, Canada 2 National Research Council Canada, Penticton, British Columbia, Canada 3 Astrophysics Group, School of Physics, University of Exeter, Exeter, United Kingdom E-mail contact: FosterT at BrandonU.CA We present a new catalogue of spectrophotometric distances and line-of-sight systemic velocities to 103 Hii regions between 90◦ l 195◦ (longitude quadrants II and part of III). Two new velocities for each region are independently measured using≤ 1≤′ resolution 21 cm H i and 2.6 mm 12CO line maps (from the Canadian Galactic Plane Survey and FCRAO Outer Galaxy Surveys) that show where gaseous shells are observed around the periphery of the ionized gas. Known and neighbouring OB-type stars with published UBV photometry and MK classiﬁcations are overlaid onto 21 cm continuum maps, and those stars observed within the boundary of the H ii emission (and whose distance is not more than 3 times the standard deviation of the others) are used to calculate new mean stellar distances to each of the 103 nebulae. Using this approach of excluding distance outliers from the mean distance to a group of many stars in each H ii region lessens the impact of anomalous reddening for certain individuals. Final mean distances of 9 common objects with VLBI parallax distances show a 1:1 correspondence. Further, comparison with previous catalogues of H ii regions in these quadrants shows a 50% reduction in scatter for the distance to Perseus spiral arm objects in the same region, and a reduction by 1/√2 in scatter around a common angular velocity relative to the Sun −1 −1 ∼ Ω Ω0(km s kpc ). The purpose of the catalogue is to provide a foundation for more detailed large-scale Galactic spiral− structure and dynamics (rotation curve, density wave streaming) studies in the 2nd and 3rd quadrants, which from the Sun’s location is the most favourably viewed section of the Galaxy. Accepted by AJ http://arxiv.org/pdf/1405.7003

Shaping a high-mass star-forming cluster through stellar feedback. The case of the NGC 7538 IRS 1–3 complex. Pau Frau1,2, Josep Miquel Girart3, Qizhou Zhang4 and Ramprasad Rao5 1 Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Inés de la Cruz 3, E-28049 Madrid, Spain 2 Observatorio Astronómico Nacional, Alfonso XII 3, E-28014 Madrid, Spain 3 Institut de Ciències de l’Espai, CSIC-IEEC, Campus UAB, Facultat de Ciències, Torre C5p 2, E-08193 Bellaterra, Catalonia, Spain 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA 5 Institute of Astronomy and Astrophysics, Academia Sinica, 645 N. Aohoku Place, Hilo HI 96720, USA E-mail contact: p.frau at oan.es

21 Context. NGC 7538 IRS 1–3 is a high-mass star-forming cluster with several detected dust cores, infrared sources, (ultra)compact H II regions, molecular outflows, and masers. In such a complex environment, important interactions and feedback among the embedded objects are expected to play a major role in the evolution of the region. Aims. We study the dust, kinematic, and polarimetric properties of the NGC 7538 IRS 1–3 region to investigate the role of the different forces interplaying in the formation and evolution of high-mass star-forming clusters. Methods. We perform SMA high angular resolution observations at 880 µm with the compact configuration. We develop the RATPACKS code to generate synthetic velocity cubes from models of choice to be compared to the observational data. We develop the “mass balance” analysis to quantify the stability against gravitational collapse accounting for all the energetics at core scales. Results. We detect 14 dust cores from 3.5 M⊙ to 37 M⊙ arranged in two larger scale structures: a central bar and a filamentary spiral arm. The spiral arm presents large scale velocity gradients in H13CO+ 4–3 and C17O 3–2, and magnetic field segments well aligned to the dust main axis. The velocity gradient is well reproduced by a spiral arm expanding at 9 km s−1 with respect to the central core MM1, which is known to power a large precessing outflow. The energy of the outflow is comparable with the spiral arm kinetic energy, which is dominant over gravitational and magnetic energies. In addition, the dynamical ages of the outflow and spiral arm are comparable. At core scales, those embedded in the central bar seem to be unstable against gravitational collapse and prone to form high-mass stars, while those in the spiral arm have lower masses that seem to be supported by non-thermal motions and magnetic fields. Conclusions. The NGC 7538 IRS 1–3 cluster seems to be dominated by proto-stellar feedback. The dusty spiral arm appears to be formed in a snow-plow fashion due to the outflow from the MM1 core. We speculate that the external pressure from the red-shifted lobe of the outflow could trigger star formation in the spiral arm cores. This scenario would form a small cluster with a few central high-mass stars, surrounded by a number of low-mass stars formed through proto-stellar feedback. Accepted by A&A http://arxiv.org/pdf/1405.6742

Long Term Evolution of Planet-Induced Vortices in Protoplanetary Disks Wen Fu1,2, Hui Li2, Stephen Lubow3, and Shengtai Li2 1 Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA 2 Los Alamos National Laboratory, Los Alamos, NM 87545, USA 3 Space Telescope Science Institute, Baltimore, MD 21218, USA E-mail contact: wf5 at rice.edu Recent observations of large-scale asymmetric features in protoplanetary disks suggest that large-scale vortices exist in such disks. Massive planets are known to be able to produce deep gaps in protoplanetary disks. The gap edges could become hydrodynamically unstable to the Rossby wave/vortex instability and form large-scale vortices. In this study we examine the long term evolution of these vortices by carrying out high-resolution two dimensional hydrodynamic simulations that last more than 104 orbits (measured at the planet’s orbit). We find that the disk viscosity has a strong influence on both the emergence and lifetime of vortices. In the outer disk region where asymmetric features are observed, our simulation results suggest that the disk viscous α needs to be low 10−5–10−4 to sustain vortices to thousands and up to 104 orbits in certain cases. The chance of finding a vortex feature∼ in a disk then decreases with smaller planet orbital radius. For α 10−3 or larger, even planets with masses of 5 Jupiter-masses will have difficulty either producing or sustaining vortices.∼ We have also studied the effects of different disk temperatures and planet masses. We discuss the implications of our findings on current and future protoplanetary disk observations. Accepted by ApJL http://arxiv.org/pdf/1405.7379

A CO survey in planet-forming disks: characterizing the gas content in the epoch of planet formation A.S. Hales1,2, I. De Gregorio-Monsalvo1,3, B. Montesinos4, S. Casassus5, W.F.R. Dent1,3, C. Dougados6, C. Eiroa7, A.M. Hughes8, G. Garay5, D. Mardones5, F. M´enard6, Aina Palau9, S. P´erez5, N. Phillips1,3, J.M. Torrelles10 and D. Wilner11

22 1 Atacama Large Millimeter/Submillimeter Array, Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura 763- 0355, Santiago - Chile 2 National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, Virginia, 22903-2475, United States 3 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748, Garching bei M¨nchen, Germany 4 Department of Astrophysics, Centre for Astrobiology (CAB, CSIC-INTA), ESAC Campus, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain 5 Departamento de Astronom´ıa, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile 6 UMI-FCA, CNRS/INSU, France (UMI 3386), and Dept. de Astronom´ıa, Universidad de Chile, Santiago, Chile 7 Departamento de F´ısica Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain 8 Department of Astronomy, University of California, Berkeley, CA 94720, USA 9 Institut de Ciéncies de l’Espai (CSIC-IEEC), Campus UAB-Facultat de Ciencies, Torre C5-parell 2, 08193 Bellaterra, Catalunya, Spain 10 Institut de Ciéncies de l’Espai (CSIC-IEEC) and Institut de Ciéncies del Cosmos (UBIEEC), Mart´ıi Franqu‘es 1, 08028 Barcelona, Spain 11 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA E-mail contact: ahales at alma.cl 12 We carried out a CO (3–2) survey of 52 southern stars with a wide range of IR excesses (LIR/L∗) using the single dish telescopes APEX and ASTE. The main aims were (1) to characterize the evolution of molecular gas in circumstellar disks using LIR/L∗ values as a proxy of disk dust evolution, and (2) to identify new gas-rich disk systems suitable for detailed study with ALMA. About 60% of the sample (31 systems) have LIR/L∗ > 0.01 typical of T-Tauri or Herbig AeBe stars, and the rest (21 systems) have LIR/L∗ < 0.01 typical of debris disks. We detect CO (3–2) emission from 20 systems, and 18 (90%) of these have LIR/L∗ > 0.01. However, the spectra of only four of the newly detected systems appear free of contamination from background or foreground emission from molecular clouds. These include the early-type stars HD 104237 (A4/5V, 116 pc) and HD 98922 (A2 III, 507 pc, as determined in this work), where our observations reveal the presence of CO-rich circumstellar disks for the first time. Of the other detected sources, many could harbor gaseous circumstellar disks, but our data are inconclusive. For these two newly discovered gas-rich disks, we present radiative transfer models that simultaneously reproduce their spectral energy distributions and the 12CO (3–2) line profiles. For both of these systems, the data are fit well by geometrically flat disks, placing them in the small class of non-flaring disks with significant molecular gas reservoirs. Accepted by AJ http://arxiv.org/pdf/1405.6966

The Disappearing Envelope around the Transitional Class I Object L43 Shin Koyamatsu1,2, Shigehisa Takakuwa3, Masahiko Hayashi4, Satoshi Mayama5 and Nagayoshi Ohashi2 1 Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan 2 Subaru Telescope, 650 North A’ohoku Place, Hilo, HI 96720, U.S.A. 3 Institute of Astronomy and Astrophysics, Academia Sinica, P. O. Box 23-141, Taipei 10641, Taiwan 4 National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588, Japan 5 Graduate University for Advanced Studies, Shonan International Village, Hayama-cho, Miura-gun, Kanagawa 240- 0193, Japan E-mail contact: shin.koyamatsu at nao.ac.jp We present SMA interferometric observations of the 12CO (J = 2–1), 13CO (J = 2–1), and C18O (J = 2–1) lines and 225 GHz continuum emission and SMT single-dish observations of C18O (J = 2–1) toward L43, a protostellar object in transition from Class I to II. The 225 GHz continuum emission shows a weak ( 23.6 mJy), compact (< 1000 AU) component associated with the central protostar. Our simulated observations show∼ that it can be explained by dust thermal emission arising from an envelope which has a hole or a constant intensity region within a few hundred AU of the protostar. This suggests the disappearance or a lower concentration distribution of the envelope on a small scale. The 12CO and 13CO emission exhibit molecular outﬂows to the south and north. The C18O emission shows two molecular blobs, which correspond to the reﬂection nebulosity seen in near-infrared images, while there is no C18O

23 emission associated with the protostar. The near-infrared features are likely due to the scattering at the positions of the blobs. The visible scattering features should result from the optical thinness of the envelope material, which is consistent with the less-concentrated distribution in the continuum emission. From single-dish observations, we found that the mass of the envelope ( 1.5 M⊙) + protostar ( 0.5 M⊙) is comparable with the virial mass of Mvir =1.0 M⊙ within 40 arcsec. This suggests∼ that the envelope is likely∼ gravitationally bound. We suggest that the protostellar envelope of L43 has been disappearing by consumption through accretion, at least in the close vicinity of the protostar. Accepted by The Astrophysical Journal http://arxiv.org/pdf/1405.5898

Feedback by massive stars and the emergence of superbubbles II. X-ray properties Martin Krause1,2, Roland Diehl1,2, Hans Böhringer1,2, Michael Freyberg1, and Daniel Lubos1 1 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, 85741 Garching, Germany 2 Excellence Cluster Universe, Technische Universität München, Boltzmannstrasse 2, 85748 Garching, Germany E-mail contact: krause at mpe.mpg.de In a previous paper we investigated the energy transfer of massive stars to the interstellar medium as a function of time and the geometrical configuration of three massive stars via 3D-mesh-refining hydrodynamics simulations, following the complete evolution of the massive stars and their supernovae except non-thermal processes. We analysed our ISM simulation results with the help of spectra for plasma temperatures between 0.1 and 10 keV and computed the spectral evolution and the spatio-temporal distribution of the hot gas. Despite significant input of high temperature gas from supernovae and fast stellar winds, the resulting thermal X-ray spectra are generally very soft, with most of the emission well below 1 keV. We show that this is due to mixing triggered by resolved hydrodynamic instabilities. Supernovae enhance the X-ray luminosity of a superbubble by 1–2 orders of magnitude for a time span of about 0.1 Myr; longer if a supernova occurs in a larger superbubble and shorter in higher energy bands. Peak superbubble luminosities of the order of 1036 erg s−1 are reproduced well. The strong decay of the X-ray luminosity is due to bubble expansion, hydrodynamic instabilities related to the acceleration of the superbubble’s shell thanks to the sudden energy input, and subsequent mixing. We also find global oscillations of our simulated superbubbles, which produce spatial variations of the X-ray spectrum, similar to what we see in the Orion-Eridanus cavity. We calculated the fraction of energy emitted in X-rays and find that with a value of a few times 10−4, it is about a factor of ten below the measurements for nearby galaxies. Accepted by A&A http://arxiv.org/pdf/1405.0037

Star-forming regions of the Aquila rift cloud complex. II. Turbulence in molecular cores probed by NH3 emission S.A. Levshakov1,2,3, C. Henkel4,5, D. Reimers1, and M. Wang6 1 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg, Germany 2 Ioffe Physical-Technical Institute, Polytekhnicheskaya Str. 26, 194021 St. Petersburg, Russia 3 St. Petersburg Electrotechnical University ‘LETI’, Prof. Popov Str. 5, 197376 St. Petersburg, Russia 4 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany 5 Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia 6 Purple Mountain Observatory, Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210008, P. R. China E-mail contact: lev at astro.ioffe.rssi.ru Aims. We intend to derive statistical properties of stochastic gas motion inside the dense low mass star forming molecular cores traced by NH3(1,1) and (2,2) emission lines. Methods. We use the spatial two-point autocorrelation (ACF) and structure functions calculated from maps of the radial velocity fields. Results. We find oscillating ACFs which eventually decay to zero with increasing lags on scales of 0.04 l 0.5 pc. The current paradigm supposes that the star formation process is controlled by the interplay between gravitation≤ ≤ and turbulence, the latter preventing molecular cores from a rapid collapse due to their own gravity. Thus, oscillating

24 ACFs may indicate a damping of the developed turbulent ﬂows surrounding the dense but less turbulent core - a transition to dominating gravitational forces and, hence, to gravitational collapse. Accepted by A&A http://arxiv.org/pdf/1405.7492

On filament L1482 in the California molecular cloud D.L. Li1,2, J. Esimbek1,3, J.J. Zhou1,3, Y.-Q. Lou4, G. Wu1,2,3, X.D. Tang1,2, and Y.X. He1,2 1 Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011, P. R. China 2 University of the Chinese Academy of Sciences, Beijing 100080, P. R. China 3 Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Urumqi 830011, P. R. China 4 Department of Physics and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 100084, P. R. China E-mail contact: lidalei at xao.ac.cn Aims. The process of gravitational fragmentation in the L1482 molecular filament of the California Molecular Cloud is studied by combining several complementary observations and physical estimates. We investigate the kinematic and dynamical states of this molecular filament and physical properties of several dozens of dense molecular clumps embedded therein. Methods. We present and compare molecular line emission observations of the J=2–1 and J=3–2 transitions of 12CO in this molecular complex, using the KOSMA 3-meter telescope. These observations are complemented with archival data observations and analyses of the 13CO J=1–0 emission obtained at the Purple Mountain Observatory 13.7- meter radio telescope at Delingha Station in QingHai Province of west China, as well as infrared emission maps from the Herschel Space Telescope online archive, obtained with the SPIRE and PACS cameras. Comparison of these complementary datasets allow for a comprehensive multi-wavelength analysis of the L1482 molecular filament. Results. We have identified 23 clumps along the molecular filament L1482 in the California Molecular Cloud. All these molecular clumps show supersonic non-thermal gas motions. While surprisingly similar in mass and size to the much more well-known Orion Molecular Cloud, the formation rate of high-mass stars appears to be suppressed in the California Molecular Cloud relative to that in the Orion Molecular Cloud based on the mass-radius threshold derived from the static Bonnor Ebert sphere. Our analysis suggests that these molecular filaments are thermally supercritical and molecular clumps may form by gravitational fragmentation along the filament. Instead of being static, these molecular clumps are most likely in processes of dynamic evolution. Accepted by A&A http://arxiv.org/pdf/1405.7454

ALMA observations of the kinematics and chemistry of disc formation Johan E. Lindberg1,2, Jes K. Jørgensen2,1, Christian Brinch2,1, Troels Haugbølle1,2, Edwin A. Bergin3, Daniel Harsono4,5, Magnus V. Persson4, Ruud Visser3 and Satoshi Yamamoto6 1 Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark 2 Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark 3 Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042, USA 4 Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden, The Netherlands 5 SRON Netherlands Institute for Space Research, P.O. Box 800, NL-9700 AV, Groningen, The Netherlands 6 Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan E-mail contact: jolindbe at gmail.com Context: The R CrA cloud hosts a handful of Class 0/I low-mass young stellar objects. The chemistry and physics at scales > 500 AU in this cloud are dominated by the irradiation from the nearby Herbig Be star R CrA. The luminous large-scale emission makes it necessary to use high-resolution spectral imaging to study the chemistry and dynamics of the inner envelopes and discs of the protostars. Aims: We aim to better understand the structure of the inner regions of these protostars and, in particular, the

25 interplay between the chemistry and the presence of discs. Methods: Using Atacama Large Millimeter/submillimeter Array (ALMA) high-resolution spectral imaging interferometry observations, we study the molecular line and dust continuum emission at submillimetre wavelengths. Results: We detect dust continuum emission from four circumstellar discs around Class 0/I objects within the R CrA cloud. Towards IRS7B we detect C17O emission showing a rotation curve consistent with a Keplerian disc with a well-defined edge that gives a good estimate for the disc radius at 50 AU. We derive the central object mass to 2.3M⊙ and the disc mass to 0.024M⊙. The observations are also consistent with a model of material infalling under conservation of angular momentum; however, this model provides a worse fit to the data. We also report a likely detection of faint CH3OH emission towards this point source, as well as more luminous CH3OH emission in an outflow orthogonal to the major axis of the C17O emission. Conclusions: The faint CH3OH emission seen towards IRS7B can be explained by a flat density profile of the inner envelope caused by the disc with a radius <50 AU. We propose that the regions of the envelopes where complex organic molecules are present in Class 0/I young∼ stellar objects can become quenched as the disc grows. Accepted by A&A http://arxiv.org/pdf/1405.1416

Constraints to the magnetospheric properties of T Tauri stars. I. The C II], Fe II] and Si II] ultraviolet features Fatima López-Mart´ınez1 and Ana Inés Gómez de Castro1 1 AEGORA Research Group, Universidad Complutense de Madrid, Plaza de Ciencias 3, 28040 Madrid, Spain E-mail contact: fatimalopezmar at gmail.com The C II] feature at 2325 A˚ is very prominent in the spectra of T Tauri stars (TTSs). This feature is a quintuplet of semiforbidden transitions∼ excited at electron temperatures around 10,000 K that, together with the nearby Si II] and Fe II] features, provides a reliable optically thin tracer for accurate measurement of the plasma properties in the magnetospheres of TTSs. The spectra of 20 (out of 27) TTSs observed with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST) have good enough signal to noise ratio (S/N) at the C II] wavelength. For these stars we have determined electron densities (ne) and temperatures (Te) in the line emission 4.1 4.5 region as well as the profile broadening (σ). For most of the stars in the sample (17) we obtain 10

Mid- and Far-Infrared Variability of PV Cep Dario Lorenzetti1, Simone Antoniucci1, Teresa Giannini1, Gianluca Li Causi1, Andrea Di Paola1, Arkady A. Arkharov2 and Valeri M. Larionov2,3 1 INAF - Osservatorio Astronomico di Roma - Via Frascati 33 - 00040 Monte Porzio Catone, Italy 2 Central Astronomical Observatory of Pulkovo - Pulkovskoe shosse 65, 196140 St.Petersburg, Russia 3 Astronomical Institute of St.Petersburg University, Russia E-mail contact: dario.lorenzetti at oa-roma.inaf.it We present the collection of all the mid- and far-IR observations (λ=3-170µm) of the young eruptive variable PV Cep available so far in the literature. These data allow us to confirm that flux variability is a prominent feature at mid-IR wavelengths (λ=3-25µm). Color-magnitude plots clearly indicate that the observed variability is not extinction-driven, but mainly influenced by fluctuations of the mass accretion rate. We interpret such variability as due to a hot spot created onto the stellar surface by the column of accreting matter, which heats the inner parts of the disk and determines the observed increase of the near- mid-IR luminosity. A quantitative characterization is given for both the

26 spot itself and the additional thermal component created by it. Far-IR data (λ=60-170µm) are consistent with the presence of a temperature stratiﬁcation in a massive and quite un-evolved circumstellar disk. Accepted by Astrophysics and Space Science http://arxiv.org/pdf/1405.7525

The W43-MM1 mini-starburst ridge, a test for star formation efficiency models Fabien Louvet1, Frédérique Motte1, Patrick Hennebelle1, Anaëlle Maury1, Ian Bonnell2, Sylvain Bontemps3, Antoine Gusdorf4, Tracey Hill5, Frédéric Gueth6, Nicolas Peretto7, Ana Duarte-Cabral8, Gwendoline Stephan9, Peter Schilke9, Timéa Csengeri10, Quang Nguyen-Luong11 and Darek Lis12 1 Laboratoire AIM Paris-Saclay, CEA/IRFU - CNRS/INSU - Université Paris Diderot, Service d’Astrophysique, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex, France 2 Universities Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK 3 OASU/LAB-UMR 5804, CNRS/INSU - UniversitéBordeaux 1, 2 rue de l’Observatoire, BP 89, F-33270 Floirac, France 4 LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole´ Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France 5 Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile 6 Institut de Radioastronomie Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint Martin d’Hères, France 7 School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA, UK 8 School of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK 9 Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany 10 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany 11 Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8, Canada 12 Sorbonne Universités, UniversitéPierre et Marie Curie, Paris 6, CNRS, Observatoire de Paris, UMR 8112, LERMA, Paris, France E-mail contact: fabien.louvet at cea.fr Star formation efficiency (SFE) theories are currently based on statistical distributions of turbulent cloud structures and a simple model of star formation from cores. They remain poorly tested, especially at the highest densities. We investigate the effects of gas density on the SFE through measurements of the core formation efficiency (CFE). With a 4 total mass of 2 10 M⊙, the W43-MM1 ridge is one of the most convincing candidate precursor of Galactic starburst clusters and thus∼ × one of the best places to investigate star formation. We used high-angular resolution maps obtained at 3 mm and 1 mm within the W43-MM1 ridge with the IRAM Plateau de Bure Interferometer to reveal a cluster of 11 massive dense cores (MDCs), and, one of the most massive protostellar cores known. An Herschel column density image provided the mass distribution of the cloud gas. We then measured the ‘instantaneous’ CFE and estimated the SFE and the star formation rate (SFR) within subregions of the W43-MM1 ridge. The high SFE found in the ridge ( 6% enclosed in 8 pc3) confirms its ability to form a starburst cluster. There is however a clear lack of dense cores in∼ the northern part∼ of the ridge, which may be currently assembling. The CFE and the SFE are observed to increase with volume gas density while the SFR per free fall time steeply decreases with the virial parameter, αvir. Statistical models of the SFR may well describe the outskirts of the W43-MM1 ridge but struggle to reproduce its inner part, which corresponds to measurements at low αvir. It may be that ridges do not follow the log-normal density distribution, Larson relations, and stationary conditions forced in the statistical SFR models. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1404.4843

Rosette Globulettes and Shells in the Infrared Minja M. Mäkelä1, Lauri K. Haikala2,1 and Gösta F. Gahm3 1 Department of Physics, Division of Geophysics and Astronomy, P.O. Box 64, 00014 University of Helsinki, Finland

27 2 Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland 3 Stockholm Observatory, AlbaNova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden E-mail contact: minja.makela at helsinki.fi Context. Giant galactic HII regions surrounding central young clusters show compressed molecular shells, which have broken up into clumps, filaments, and elephant trunks interacting with UV light from central OB stars. Tiny, dense clumps of sub-solar mass, called globulettes, form in this environment. Aims. We observe and explore the nature and origin of the infrared emission and extinction in such cool, dusty shell features and globulettes in one such HII region, the Rosette Nebula, and search for associated newborn stars. Methods. We imaged the northwestern quadrant of the Rosette Nebula in the near-infrared (NIR) through wide-band JHKs filters and narrow-band H2 1–0 S(1) and Pβ plus continuum filters using SOFI at the New Technology Telescope (NTT) at ESO. NIR images were used to study the surface brightness of the globulettes and associated bright rims. NIR JHKs photometry was used to create a visual extinction map and to search for objects with NIR excess emission. In addition, archival images from Spitzer IRAC and MIPS 24 µm and Herschel PACS observations, covering several bands in the mid-infrared (MIR) and far-infrared (FIR), were used to further analyze the stellar population, to examine the structure of the trunks and other shell structures and to study this Rosette Nebula photon-dominated region in more detail. Results. The globulettes and elephant trunks have bright rims in the Ks band, which are unresolved in our images, on the sides facing the central cluster. Analysis of 21 globulettes where surface brightness in the H2 1–0 S(1) line at 2.12 µm is detected shows that approximately a third of the surface brightness observed in the Ks filter is due to this line: the observed average of the H2/Ks surface brightness is 0.26 0.02 in the globulettes cores and 0.30 0.01 in the rims. The estimated H 1–0 S(1) surface brightness of the rims is± 3–8 10−8 Wm−2sr−1µm−1. The ratio± of 2 ∼ × the surface brightnesses support fluorescence instead of shocks as the H2 excitation mechanism. The globulettes have −4 −3 number densities of n(H2) 10 cm or higher. Masses of individual globulettes were estimated and compared to the results from previous∼ optical and radio molecular line surveys. We confirm that the larger globulettes contain very dense cores, that the density is high also farther out from the core, and that their mass is sub-solar. Two NIR protostellar objects were found in an elephant trunk and one in the most massive globulette in our study. Accepted by Astronomy & Astrophysics http://arxiv.org/pdf/1405.5778

Revisiting the universality of (multiple) star formation in present-day star formation regions Michael Marks1, Nathan Leigh2,3, Mirek Giersz4, Susanne Pfalzner5, Jan Pamm-Altenburg1, Seungkyung Oh1 1 Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, D-53115 Bonn 2 Department of Astrophysics, American Museum of Natural History, Central Park West and 79th Street, NY 10024, USA 3 Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB T6G 2E1, Canada 4 Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, Poland 5 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany E-mail contact: mmarks at astro.uni-bonn.de Populations of multiple stars inside clustered regions are known to change through dynamical interactions. The efficiency of binary disruption is thought to be determined by stellar density. King and collaborators recently investigated the multiplicity properties in young star forming regions and in the Galactic field. They concluded that stellar density- dependent modification of a universal initial binary population (the standard or null hypothesis model) cannot explain the observations. We re-visit their results, analyzing the data within the framework of different model assumptions, namely non-universality without dynamical modification and universality with dynamics. We illustrate that the standard model does account for all known populations if regions were significantly denser in the past. Some of the effects of using present-day cluster properties as proxies for their past values are emphasized and that the degeneracy between age and density of a star forming region can not be omitted when interpreting multiplicity data. A new analysis of the Corona Australis region is performed within the standard model. It is found that this region is likely as unevolved −3 as Taurus and an initial density of 190 M⊙ pc is required to produce the presently observed binary population, ≈

28 which is close to its present-day density. Accepted by MNRAS http://arxiv.org/pdf/1405.3984

Stellar parameters and accretion rate of the transition disk star HD 142527 from X- Shooter I. Mendigut´ıa1, J. Fairlamb1, B. Montesinos2, R.D. Oudmaijer1, J.R. Najita3, S.D. Brittain4, and M.E. van den Ancker5 1 School of Physics & Astronomy, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK 2 Centro de Astrobiolog´ıa, Departamento de Astrof´ısica (CSIC-INTA), ESAC Campus, P.O. Box 78, 28691 Villanueva de la Cañada, Madrid, Spain 3 National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719, USA 4 Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978, USA 5 European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching b. München, Germany E-mail contact: I.Mendigutia at leeds.ac.uk HD 142527 is a young pre-main sequence star with properties indicative of the presence of a giant planet or/and a low-mass stellar companion. We have analyzed an X-Shooter/Very Large Telescope spectrum to provide accurate stellar parameters and accretion rate. The analysis of the spectrum, together with constraints provided by the SED fitting, the distance to the star (140 20 pc) and the use of evolutionary tracks and isochrones, lead to the following ± set of parameters Teff = 6550 100 K, log g = 3.75 0.10, L∗/L⊙ = 16.3 4.5, M∗/M⊙ = 2.0 0.3 and an age of 5.0 1.5 Myr. This stellar age± provides further constrains± to the mass of the± possible companion± estimated by Biller ± et al. (2012), being in-between 0.20 and 0.35 M⊙. Stellar accretion rates obtained from UV Balmer excess modelling, optical photospheric line veiling, and from the correlations with several emission lines spanning from the UV to the −7 −1 near-IR, are consistent to each other. The mean value from all previous tracers is (2 1) 10 M⊙ yr , which is within the upper limit gas flow rate from the outer to the inner disk recently provided± by Cassasus× et al. (2013). This suggests that almost all gas transferred between both components of the disk is not trapped by the possible planet(s) in-between but fall onto the central star, although it is discussed how the gap flow rate could be larger than previously suggested. In addition, we provide evidence showing that the stellar accretion rate of HD 142527 has increased by a factor 7 on a timescale of 2–5 years. ∼ Accepted by ApJ http://arxiv.org/pdf/1405.7378

Very deep images of the innermost regions of the β Pictoris debris disc at L′ J. Milli1,2, A.-M. Lagrange1, D. Mawet2, O. Absil3, J.-C. Augereau1, D. Mouillet1, A. Boccaletti4, J.H. Girard2, and G. Chauvin1 1 UniversitéGrenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble, France 2 European Southern Observatory (ESO), Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago, Chile 3 Département d’Astrophysique, Géophysique et Océanographie (AGO), Universitéde Liège, 17 Allée du Six Août, B-4000 Liège, Belgium 4 LESIA, Observatoire de Paris, CNRS, Universit Pierre et Marie Curie 6 and Universit Denis Diderot Paris 7, 5 place Jules Janssen, 92195 Meudon, France E-mail contact: jmilli at eso.org Very few debris discs have been imaged in scattered light at wavelengths beyond 3 µm because the thermal emission from both the sky and the telescope is generally too strong with respect to the faint emission of a debris disc. We present here the first analysis of a high angular resolution image of the disc of β Pictoris at 3.8 µm. Our primary objective is to probe the innermost parts of the β Pictoris debris disc and describe its morphology. We performed extensive forward modelling to correct for the biases induced by angular differential imaging on extended objects and derive the physical parameters of the disc. This work relies on a new analysis of seven archival datasets of β

29 Pictoris observed with VLT/NaCo in the L′ band, associated with disc forward modelling to correct for the biases induced by that technique. The disc is detected above a 5σ level between 0′′. 4 and 3′′. 8. The two extensions have a similar brightness within error bars. We confirm an asymmetry previously observed at larger distances from the star and at shorter wavelengths: the isophotes are more widely spaced on the north-west side (above the disc apparent midplane) than on the south-east side. This is interpreted as a small inclination of the disc combined with anisotropic scattering. Our best-fit model has an inclination of 86◦ with an anisotropic Henyey- Greenstein coefficient of 0.36. This interpretation is supported by a new asymmetry detected in the disc: the disc is significantly bowed towards the north-west within 3′′ (above the apparent midplane). We also detect a possible new asymmetry within 1′′, but at this stage we cannot discern between a real feature and an underlying speckle. Accepted by A&A http://arxiv.org/pdf/1405.2536

Grain growth in the envelopes and disks of Class I protostars A. Miotello1,2, L. Testi1,3,4, G. Lodato2, L. Ricci5, G. Rosotti4,6, K. Brooks7, A. Maury8 and A. Natta3,9 1 European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany 2 Universit degli Studi di Milano, Dipartimento di Fisica, Via Celoria 16, I-20133 Milano, Italy 3 INAF-Osservatorio Astroﬁdico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy 4 Excellence Cluster Universe, Boltzmannstr. 2, D-85748 Garching, Germany 5 Department of Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125, USA 6 Max-Planck-institute fr extraterrestrische Physik, Giessenbachstraße, D-85748 Garching, Germany 7 Australia Telescope National Facility, P.O. Box 76, Epping NSW 1710, Australia 8 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 9 School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland E-mail contact: miotello at mpe.mpg.de We present new 3 mm ATCA data of two Class I Young Stellar Objects in the Ophiucus star forming region: Elias29 and WL12. For our analysis we compare them with archival 1.1 mm SMA data. In the (u, v) plane the two sources present a similar behavior: a nearly constant non-zero emission at long baselines, which suggests the presence of an unresolved component and an increase of the ﬂuxes at short baselines, related to the presence of an extended envelope. Our data analysis leads to unusually low values of the spectral index α1.1−3mm, which may indicate that mm-sized dust grains have already formed both in the envelopes and in the disk-like structures at such early stages. To explore the possible scenarios for the interpretation of the sources we perform a radiative transfer modeling using a Monte Carlo code, in order to take into account possible deviations from the Rayleigh-Jeans and optically thin regimes. Comparison between the model outputs and the observations indicates that dust grains may form aggregates up to millimeter size already in the inner regions of the envelopes of Class I YSOs. Moreover, we conclude that the embedded disk-like structures in our two Class Is are probably very compact, in particular in the case of WL12, with outer radii down to tens of AU. Accepted by A&A http://arxiv.org/pdf/1405.0821

Chemistry in an Evolving Protoplanetary Disk: Eﬀects on Terrestrial Planet Composi- tion John Moriarty1, Nikku Madhusudhan2,3, and Debra Fischer1 1 Department of Astronomy, Yale University, New Haven, CT 06511, USA 2 Departments of Physics and Astronomy, Yale University, New Haven, CT 06511, USA 3 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK E-mail contact: john.c.moriarty at yale.edu The composition of planets is largely determined by the chemical and dynamical evolution of the disk during planetesimal formation and growth. To predict the diversity of exoplanet compositions, previous works modeled planetesimal composition as the equilibrium chemical composition of a protoplanetary disk at a single time. However, planetes-

30 imals form over an extended period of time, during which, elements sequentially condense out of the gas as the disk cools and are accreted onto planetesimals. To account for the evolution of the disk during planetesimal formation, we couple models of disk chemistry and dynamics with a prescription for planetesimal formation. We then follow the growth of these planetesimals into terrestrial planets with N-body simulations of late stage planet formation to evaluate the eﬀect of sequential condensation on the bulk composition of planets. We ﬁnd that our model produces results similar to those of earlier models for disks with C/O ratios close to the solar value (0.54). However, in disks with C/O ratios greater than 0.8, carbon rich planetesimals form throughout a much larger radial range of the disk. Furthermore, our model produces carbon rich planetesimals in disks with C/O ratios as low as 0.65, which is not possible in the static equilibrium chemistry case. These results suggest that (1) there may be a∼ large population of short period carbon rich planets around moderately carbon enhanced stars (0.65 < C/O < 0.8) and (2) carbon rich planets can form throughout the terrestrial planet region around carbon rich stars (C/O > 0.8). Accepted by ApJ http://arxiv.org/pdf/1405.3253

Discovery of a wide planetary-mass companion to the young M3 star GU Psc Marie-Eve Naud1, Etienne´ Artigau1, Lison Malo1, Lo¨ıc Albert1, RenéDoyon1, David Lafreniére1, Jonathan Gagné1, Didier Saumon2, Caroline V. Morley3, France Allard4, Derek Homeier4, Charles A. Beichman5, Christopher R. Gelino5,6, and Anne Boucher1 1 Département de physique and Observatoire du Mont-Mégantic, Universitéde Montréal, Montréal H3C 3J7, Canada 2 Los Alamos National Laboratory, Los Alamos, NM 87545, USA 3 Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA 4 Centre de Recherche Astrophysique de Lyon, UMR 5574 CNRS, Universitéde Lyon, Ecole´ Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07, France 5 Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125, USA 6 NASA Exoplanet Science Institute, California Institute of Technology, 770 S. Wilson Ave., Pasadena, CA 91125, USA E-mail contact: naud at astro.umontreal.ca We present the discovery of a co-moving planetary-mass companion 42′′ ( 2000 AU) from a young M3 star, GU Psc, likely member of the young AB Doradus Moving Group (ABDMG).∼ The∼ companion was first identified via its distinctively red i z color (>3.5) through a survey made with Gemini-S/GMOS. Follow-up Canada-France-Hawaii Telescope/WIRCam− near-infrared (NIR) imaging, Gemini-N/GNIRS NIR spectroscopy and Wide-field Infrared Survey Explorer photometry indicate a spectral type of T3.5 1 and reveal signs of low gravity which we attribute to youth. Keck/Adaptive Optics NIR observations did not resolve± the companion as a binary. A comparison with atmosphere models indicates Teff = 1000–1100 K and log g = 4.5–5.0. Based on evolution models, this temperature corresponds to a mass of 9–13 MJup for the age of ABDMG (70–130 Myr). The relatively well-constrained age of this companion and its very large angular separation to its host star will allow its thorough characterization and will make it a valuable comparison for planetary-mass companions that will be uncovered by forthcoming planet-finder instruments such as Gemini Planet Imager and SPHERE. Accepted by ApJ http://arxiv.org/pdf/1405.2932

Accreting planets as dust dams in ‘transition’ discs James E. Owen1 1 Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, M5S 3H8, Canada E-mail contact: jowen at cita.utoronto.ca We investigate under what circumstances an embedded planet in a protoplanetary disc may sculpt the dust distribution such that it observationally presents as a ‘transition’ disc. We concern ourselves with ‘transition’ discs that have large −9 −8 −1 holes (>10 AU) and high accretion rates ( 10 –10 M⊙ yr ). Particularly, those discs which photoevaporative models∼ struggle to explain. Assuming the∼ standard picture for how massive planets sculpt their parent discs, along

31 with the observed accretion rates in ‘transition’ discs, we find that the accretion luminosity from the forming planet is significant, and can dominate over the stellar luminosity at the gap edge. This planetary accretion luminosity can apply a significant radiation pressure to small (s < 1 µm) dust particles provided they are suitably decoupled from the gas. Secular evolution calculations that account∼ for the evolution of the gas and dust components in a disc with an embedded, accreting planet, show that only with the addition of the radiation pressure can we explain the full observed characteristics of a ‘transition’ disc (NIR dip in the SED, mm cavity and high accretion rate). At suitably high planet masses (>3–4 MJ), radiation pressure from the accreting planet is able to hold back the small dust particles, producing a heavily∼ dust-depleted inner disc that is optically thin (vertically and radially) to Infra-Red radiation. We use our models to calculate synthetic observations and present a observational evolutionary scenario for a forming planet, sculpting its parent disc. The planet-disc system will present as a ‘transition’ disc with a dip in the SED, only when the planet mass and planetary accretion rate is high enough. At other times it will present as a disc with a primordial SED, but with a cavity in the mm, as observed in a handful of protoplanetary discs. Accepted by ApJ http://arxiv.org/pdf/1405.3283

Resolved images of the protoplanetary disk around HD 100546 with ALMA Jaime E. Pineda1, Sascha P. Quanz1, Farzana Meru1, Gijs D. Mulders2, Michael R. Meyer1, Olja Panić3, and Henning Avenhaus1 1 Institute for Astronomy, ETH Zurich, Wolfgang-PauliStrasse 27, 8093 Zurich, Switzerland 2 Lunar and Planetary Laboratory, The University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, USA 3 Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UK E-mail contact: pjaime at phys.ethz.ch The disk around the Herbig Ae/Be star HD 100546 has been extensively studied and it is one of the systems for which there are observational indications of ongoing and/or recent planet formation. However, up until now no resolved image of the millimeter dust emission or the gas has been published. We present the first resolved images of the disk around HD 100546 obtained in Band 7 with the ALMA observatory. The CO (3–2) image reveals a gas disk that extends out to 350 AU radius at the 3σ level. Surprisingly, the 870 µm dust continuum emission is compact (radius <60 AU) and asymmetric. The dust emission is well matched by a truncated disk with outer radius of 50 AU. The lack of millimeter-sized particles outside the 60 AU is consistent with radial drift of particles of this size.∼ The protoplanet candidate, identified in previous high-contrast NACO/VLT L′ observations, could be related to the sharp outer edge of the millimeter-sized particles. Future higher angular resolution ALMA observations are needed to determine the detailed properties of the millimeter emission and the gas kinematics in the inner region (<2′′). Such observations could also reveal the presence of a planet through the detection of circumplanetary disk material. Accepted by ApJL http://arxiv.org/pdf/1405.5773

The Herschel view of circumstellar discs: a multiwavelength study of Chamaeleon I Donna Rodgers-Lee1, Alexander Scholz1,2, Antonella Natta1,3 and Tom Ray1 1 School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland 2 School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS 3 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 1-50125, Firenze, Italy E-mail contact: donna at cp.dias.ie We present the results of a multi-wavelength study of circumstellar discs around 44 young stellar objects in the 3 Myr old nearby Chamaeleon-I star-forming region. In particular, we explore the far-infrared/submm regime using Herschel fluxes. We show that Herschel fluxes at 160-500µmcan be used to derive robust estimates of the disc mass. The median disc mass is 0.005M⊙ for a sample of 28 Class IIs and 0.006M⊙ for 6 transition disks (TDs). The fraction of objects in Chamaeleon I with at least the ‘minimum mass solar nebula’ is 2-7%. This is consistent with previously published results for Taurus, IC348, ρ Oph. Diagrams of spectral slopes show the effect of specific evolutionary processes in circumstellar discs. Class II objects show a wide scatter that can be explained by dust settling. We identify a continuous trend from Class II to TDs. Including Herschel fluxes in this type of analysis highlights the diversity of

32 TDs. We find that TDs are not significantly different to Class II discs in terms of far-infrared luminosity, disc mass or degree of dust settling. This indicates that inner dust clearing occurs independently from other evolutionary processes in the discs. Accepted by MNRAS http://arxiv.org/pdf/1405.3833

Radio Continuum Sources associated with the HH 92 and HH 34 Jets Luis F. Rodr´ıguez1,2, Bo Reipurth3,4 and Hsin-Fang Chiang3,4 1 Centro de Radioastronom´ıay Astrof´ısica, Universidad Nacional Autónoma de México, Campus Morelia 2 Astronomy Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia 3 Institute for Astronomy, University of Hawaii at Manoa, Hilo, HI, USA 4 NASA Astrobiology Institute, University of Hawaii at Manoa, Hilo, HI, USA E-mail contact: l.rodriguez at crya.unam.mx We present high angular resolution, high sensitivity 8.46 GHz (3.6 cm) radio continuum observations made toward the core of the HH 92 outflow with the Very Large Array in 2002-2003 and with the Expanded Very Large Array in 2011. We detect a group of three compact sources distributed in a region 2′′ in extension and discuss their nature. We conclude that one of the objects (VLA 1) is the exciting source of the giant outflow associated with HH 92. In the case of HH 34 we present new 43.3 GHz (7 mm) observations that reveal the presence of a structure associated with the exciting source and elongated perpendicular to the highly collimated optical jet in the region. We propose that this 7 mm source is a circumstellar disk with radius of 80 AU and mass of 0.21 M⊙. ∼ ∼ Accepted by Revista Mexicana de Astronom´ıay Astrof´ısica http://arxiv.org/pdf/1405.6638

Diversity of planetary systems in low-mass disks: Terrestrial-type planet formation and water delivery M.P. Ronco1 and G.C. de El´ıa1 1 Facultad de Ciencias Astronómicas y Geof´ısicas, Universidad Nacional de La Plata and Instituto de Astrofsica de La Plata, CCT La Plata-CONICET-UNLP, Paseo del Bosque S/N (1900), La Plata, Argentina E-mail contact: mpronco at fcaglp.unlp.edu.ar Several studies, observational and theoretical, suggest that planetary systems with only rocky planets should be the most common in the Universe. We study the diversity of planetary systems that might form around Sun-like stars in low-mass disks without giant planets. We focus on the formation process of terrestrial planets in the habitable zone (HZ) and analyze their water contents with the goal to determine systems of astrobiological interest. Besides, we study the formation of planets on wide orbits because they can be detected with the microlensing technique. N-body simulations of high resolution (embryos + planetesimals) are developed for a wide range of surface density profiles. The surface density profile combines a power law to the inside of the disk of the form r−γ , with an exponential decay to the outside. We adopt a disk of 0.03 M⊙ and values of γ = 0.5, 1 and 1.5. All our simulations form planets in the HZ with different masses and final water contents depending on the 3 profiles. For γ = 0.5, we produce 3 planets in the HZ with masses between 0.03 M⊕ to 0.1 M⊕ and water contents between 0.2 and 16 Earth oceans. For γ = 1, 3 planets form in the HZ with masses between 0.18 M⊕ and 0.52 M⊕ and water contents from 34 to 167 Earth oceans. For γ = 1.5, we find 4 planets in the HZ with masses from 0.66 M⊕ to 2.21 M⊕ and water contents between 192 and 2326 Earth oceans. This profile shows distinctive results because it is the only one of those studied here that leads to the formation of water worlds. Since planetary systems with γ = 1 and 1.5 present planets in the HZ with suitable masses to retain a long-live atmosphere and to maintain plate tectonics, they seem to be the most outstanding candidates to be potentially habitable. Particularly, these systems form Earths and Super-Earths near the snow line which can be discovered by microlensing. Accepted by A&A http://arxiv.org/pdf/1405.1986

33 Numerical simulations of stellar jets and comparison between synthetic and observed maps: clues to the launch mechanism F. Rubini1, L. Maurri1, G. Inghirami1,2, F. Bacciotti3, and L. Del Zanna1,2,3 1 Dipartimento di Fisica e Astronomia, Universitádi Firenze, Via G. Sansone 1, I-50019, Sesto F. no (Firenze), Italy 2 INFN - Sezione di Firenze, Via G. Sansone 1, I-50019, Sesto F. no (Firenze), Italy 3 INAF - Osservatorio Astrosico di Arcetri, Largo E. Fermi 5, I-50125, Firenze, Italy E-mail contact: rubini at arcetri.astro.it High angular resolution spectra obtained with the Hubble Space Telescope Imaging Spectrograph (HST/STIS) provide rich morphological and kinematical information about the stellar jet phenomenon, which allows us to test theoretical models efficiently. In this work, numerical simulations of stellar jets in the propagation region are executed with the PLUTO code, by adopting inflow conditions that arise from former numerical simulations of magnetized outflows, accelerated by the disk-wind mechanism in the launching region. By matching the two regions, information about the magneto-centrifugal accelerating mechanism underlying a given astrophysical object can be extrapolated by comparing synthetic and observed position-velocity diagrams (PVDs). We show that quite different jets, like those from the young T Tauri stars DG-Tau and RW-Aur, may originate from the same disk-wind model for different configurations of the magnetic field at the disk surface. This result supports the idea that all the observed jets may be generated by the same mechanism. Accepted by A&A http://arxiv.org/pdf/1405.7499

Old pre-main-sequence Stars: Disc reformation by Bondi-Hoyle accretion P. Scicluna1,2, G. Rosotti3,4,5, J.E. Dale4 and L. Testi2,6 1 ITAP, Universitaet zu Kiel, Leibnizstr. 15, 24118 Kiel, Germany 2 European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching b. Muenchen, Germany 3 Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrae, D-85748 Garching, Germany 4 Excellence Cluster Universe, Boltzmannstr. 2, D-85748 Garching, Germany 5 Universitats-Sternwarte Muenchen, Scheinerstrae 1, D-81679 Muenchen, Germany 6 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze, Italy E-mail contact: pscicluna at astrophysik.uni-kiel.de Young stars show evidence of accretion discs which evolve quickly and disperse with an e-folding time of 3Myr. This is in striking contrast with recent observations that suggest evidence for numerous > 30 Myr old stars with∼ an accretion disc in large star-forming complexes. We consider whether these observations of apparently old accretors could be explained by invoking Bondi-Hoyle accretion to rebuild a new disc around these stars during passage through a clumpy molecular cloud. We combine a simple Monte Carlo model to explore the capture of mass by such systems with a viscous evolution model to infer the levels of accretion that would be observed. We find that a significant fraction of stars may capture enough material via the Bondi-Hoyle mechanism to rebuild a disc of mass > 1 minimum-mass solar nebula, and <10% accrete at observable levels at any given time. A significant fraction of the∼ observed old accretors may be explained∼ with our proposed mechanism. Such accretion may provide a chance for a second epoch of planet formation, and have unpredictable consequences for planetary evolution. Accepted by A&A http://arxiv.org/pdf/1405.6051

Gravito-Turbulent Disks in 3D: Turbulent Velocities vs. Depth Ji-Ming Shi1,2 and Eugene Chiang1,2,3 1 Department of Astronomy, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411, USA 2 Center for Integrative Planetary Science, UC Berkeley, Hearst Field Annex B-20, Berkeley, CA 94720-3411, USA 3 Department of Earth and Planetary Science, UC Berkeley, 307 McCone Hall, Berkeley, CA 94720-4767, USA E-mail contact: jmshi at berkeley.edu

34 Characterizing turbulence in protoplanetary disks is crucial for understanding how they accrete and spawn planets. Recent measurements of spectral line broadening promise to diagnose turbulence, with different lines probing different depths. We use 3D local hydrodynamic simulations of cooling, self-gravitating disks to resolve how motions driven by “gravito-turbulence” vary with height. We find that gravito-turbulence is practically as vigorous at altitude as at depth: even though gas at altitude is much too rarefied to be itself self-gravitating, it is strongly forced by self- gravitating overdensities at the midplane. The long-range nature of gravity means that turbulent velocities are nearly uniform vertically, increasing by just a factor of 2 from midplane to surface, even as the density ranges over nearly three orders of magnitude. The insensitivity of gravito-turbulence to height contrasts with the behavior of disks afflicted by the magnetorotational instability (MRI); in the latter case, non-circular velocities increase by at least a factor of 15 from midplane to surface, with various non-ideal effects only magnifying this factor. The distinct vertical profiles of gravito-turbulence vs. MRI turbulence may be used in conjunction with measurements of non-thermal linewidths at various depths to identify the source of transport in protoplanetary disks. Accepted by ApJ http://arxiv.org/pdf/1405.3291

The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster Gamma Velorum L. Spina1,2, S. Randich1, F. Palla1, G.G. Sacco1, L. Magrini1, E. Franciosini1, L. Morbidelli1, L. Prisinzano3, E.J. Alfaro4, K. Biazzo5, A. Frasca5, J.I. González Hernández6,7, S.G. Sousa8,9, V. Adibekyan8, E. Delgado-Mena8, D. Montes10, H. Tabernero10, A. Klutsch5, G. Gilmore11, S. Feltzing12, R.D. Jeffries13, G. Micela3, A. Vallenari14, T. Bensby11, A. Bragaglia15, E. Flaccomio13, S. Koposov10, A.C. Lanzafame16, E. Pancino15, A. Recio-Blanco18, R. Smiljanic19,20, M. T. Costado4, F. Damiani3, V. Hill18, A. ourihane10, P. Jofré10, P. de Laverny18, T. Masseron10, C. Worley11 1 INAFOsservatorio Astrosico di Arcetri, Largo E. Fermi, 5, I-50125 Firenze, Italy 2 Universitádegli Studi di Firenze, Dipartimento di Fisica e Astrosica, Sezione di Astronomia, Largo E. Fermi, 2, I-50125, Firenze, Italy 3 INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134, Palermo, Italy 4 Instituto de Astrof´ısica de Andaluc´ıa-CSIC, Apdo. 3004, 18080 Granada, Spain 5 INAFOsservatorio Astrosico di Catania, via S. Soa, 78, I-95123 Catania, Italy 6 Instituto de Astrosica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain 7 Depto. Astrosica, Universidad de La Laguna (ULL), E-38206 La Laguna, Tenerife, Spain 8 Centro de Astrosica, Universidade do Porto, Rua das Estrelas, 4150-762, Porto, Portugal 9 Departamento de F´ısica e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169- 007 Porto, Portugal 10 Departamento de Astrosica, Universidad Complutense de Madrid (UCM), Spain 11 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, United Kingdom 12 Lund Observatory, Department of Astronomy and Theoretical Physics, Box 43, SE-221 00 Lund, Sweden 13 Astrophysics Group, Research Institute for the Environment, Physical Sciences and Applied Mathematics, Keele University, Keele, Staordshire ST5 5BG, United Kingdom 14 INAF - Padova Observatory, Vicolo dell’Osservatorio 5, 35122 Padova, Italy 15 INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127, Bologna, Italy 16 Dipartimento di Fisica e Astronomia, Sezione Astrosica, Universitá di Catania, via S. Soa 78, 95123, Catania, Italy 17 ASI Science Data Center, Via del Politecnico SNC, 00133 Roma, Italy 18 Universitéde Nice Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, BP 4229, F-06304, Nice Cedex 4, France 19 Department for Astrophysics, Nicolaus Copernicus Astronomical Center, ul. Rabiańska 8, 87-100 Toruń, Poland 20 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei Munchen, Germany E-mail contact: lspina at arcetri.astro.it Knowledge of the abundance distribution of star forming regions and young clusters is critical to investigate a variety of issues, from triggered star formation and chemical enrichment by nearby supernova explosions to the ability to form planetary systems.In spite of this, detailed abundance studies are currently available for relatively few regions.

35 In this context, we present the analysis of the metallicity of the Gamma Velorum cluster, based on the products distributed in the first internal release of the Gaia-ESO Survey. The Gamma Velorum candidate members have been observed with FLAMES, using both UVES and Giraffe, depending on the target brightness and spectral type. In order to derive a solid metallicity determination for the cluster, membership of the observed stars must be first assessed. To this aim, we use several membership criteria including radial velocities, surface gravity estimates, and the detection of the photospheric lithium line. Out of the 80 targets observed with UVES, we identify 14 high-probability members. We find that the metallicity of the cluster is slightly subsolar, with a mean [Fe/H] = 0.057 0.018 dex. Although J08095427 4721419 is one of the high-probability members, its metallicity is significantly− larger± than the − cluster average. We speculate about its origin as the result of recent accretion episodes of rocky bodies of 60 M⊕ hydrogen-depleted material from the circumstellar disk. ∼ Accepted by A&A http://arxiv.org/pdf/1405.6586

Rapidly increasing collimation and magnetic field changes of a protostellar H2O maser outflow G. Surcis1, W.H.T. Vlemmings2, H.J. van Langevelde1,3, C. Goddi1, J.M. Torrelles4, J. Cantó5, S. Curiel5, S.-W. Kim6 and J.-S. Kim7 1 Joint Institute for VLBI in Europe, Postbus 2, 79990 AA Dwingeloo, The Netherlands 2 Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala, Sweden 3 Sterrewacht Leiden, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands 4 Institut de Ciències de l’Espai (CSIC)-Institut de Ciències del Cosmos (UB)/IEEC, E-08028 Barcelona, Spain 5 Instituto de Astronom´ıa(UNAM), Apdo Postal 70-264, Cd. Universitaria, 04510-México D.F., México 6 Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348, Republic of Korea 7 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan E-mail contact: surcis at jive.nl Context. W75N(B) is a massive star-forming region that contains three radio continuum sources (VLA 1, VLA 2, and VLA 3), which are thought to be three massive young stellar objects at three different evolutionary stages. VLA1 is the most evolved and VLA2 the least evolved source. The 22 GHz H2O masers associated with VLA1 and VLA2 have been mapped at several epochs over eight years. While the H2O masers in VLA 1 show a persistent linear distribution along a radio jet, those in VLA 2 are distributed around an expanding shell. Furthermore, H2O maser polarimetric measurements revealed magnetic fields aligned with the two structures. Aims. Using new polarimetric observations of H2O masers, we aim to confirm the elliptical expansion of the shell- like structure around VLA 2 and, at the same time, to determine if the magnetic fields around the two sources have changed. Methods. The NRAO Very Long Baseline Array was used to measure the linear polarization and the Zeeman-splitting of the 22 GHz H2O masers towards the massive star-forming region W75N(B). Results. The H2O maser distribution around VLA 1 is unchanged from that previously observed. We made an elliptical fit of the H2O masers around VLA 2. We find that the shell-like structure is still expanding along the direction parallel to the thermal radio jet of VLA 1. While the magnetic field around VLA 1 has not changed in the past 7 years, the magnetic field around VLA 2 has changed its orientation according to the new direction of the major-axis∼ of the shell-like structure and it is now aligned with the magnetic field in VLA 1. Accepted by Astronomy & Astrophysics Letters

Distribution of CCS and HC3N in L1147, an Early Phase Dark Cloud Taiki Suzuki1, Masatoshi Ohishi1,2, and Tomoya Hirota1,2 1 Department of Astronomical Science, the Graduate University for Advanced Studies (SOKENDAI), Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan 2 National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588, Japan E-mail contact: taiki.suzuki at nao.ac.jp

36 We used the Nobeyama 45 m radio telescope to reveal spatial distributions of CCS and HC3N in L1147, one of carbon- chain producing regions (CCPRs) candidates, where carbon-chain molecules are dominant rather than NH3. We found that three cores (two CCS cores and one HC3N core) exist along the NE–SW filament traced by the 850 µm dust continuum, which are away from a Very Low Luminosity Object (VeLLO - a source that may turn into sub-stellar 12 −2 12 −2 mass brown dwarf). The column densities of CCS are 3–7 10 cm and those of HC3N are 2–6 10 cm , respectively, much lower than those previously reported towards× other CCPRs. We also found that two× CCS peaks are displaced from that of HC3N. In order to interpret such interleaved distributions, we conducted chemical reaction network simulations, and found that slightly different gas densities could lead to large variation of CCS-to-HC3N ratio in the early phase of dark cloud evolution. Such a chemical “variation” may be seen in other CCPRs. Finally we were able to confirm that the L1147 filament can be regarded as a CCPR. Accepted by ApJ http://arxiv.org/pdf/1405.1500

Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores Vianney Taquet1,2, Steven B. Charnley2, and Olli Sipil¨a3 1 NASA Postdoctoral Program Fellow 2 Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770, USA 3 Department of Physics, PO Box 64, 00014 University of Helsinki, Finland E-mail contact: vianney.taquet at nasa.gov Extremely large deuteration of several molecules has been observed towards prestellar cores and low-mass protostars for a decade. New observations performed towards low-mass protostars suggest that water presents a lower deuteration in the warm inner gas than in the cold external envelope. We coupled a gas-grain astrochemical model with a one- dimension model of collapsing core to properly follow the formation and the deuteration of interstellar ices as well as their subsequent evaporation in the low-mass protostellar envelopes with the aim of interpreting the spatial and temporal evolutions of their deuteration. The astrochemical model follows the formation and the evaporation of ices with a multilayer approach and also includes a state-of-the-art deuterated chemical network by taking the spin states of H2 and light ions into account. Because of their slow formation, interstellar ices are chemically heterogeneous and show an increase of their deuterium fractionation towards the surface. The diﬀerentiation of the deuteration in ices induces an evolution of the deuteration within protostellar envelopes. The warm inner region is poorly deuterated because it includes the whole molecular content of ices while the deuteration predicted in the cold external envelope scales with the highly deuterated surface of ices. We are able to reproduce the observed evolution of water deuteration within protostellar envelopes but we are still unable to predict the super-high deuteration observed for formaldehyde and methanol. Finally, the extension of this study to the deuteration of complex organics (COMs), important for the prebiotic chemistry, shows a good agreement with the observations, suggesting that we can use the deuteration to retrace their mechanisms and their moments of formation. Accepted by ApJ http://arxiv.org/pdf/1405.3268

Thermal Starless Ammonia Core Surrounded by CCS in the Orion A Cloud Ken’ichi Tatematsu1,2, Tomoya Hirota1,2, Satoshi Ohashi3, Minho Choi4, Jeong-Eun Lee5, Satoshi Yamamoto6, Tomofumi Umemoto1,2, Ryo Kandori1, Miju Kang4 and Norikazu Mizuno1,3 1 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 2 Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 3 Department of Astronomy, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan 4 Korea Astronomy and Space Science Institute, Daedeokdaero 776, Yuseong, Daejeon 305-348, South Korea 5 School of Space Research, Kyung Hee University, Seocheon-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do, 446-701,

37 South Korea 6 Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan E-mail contact: k.tatematsu at nao.ac.jp We imaged two starless molecular cloud cores, TUKH083 and TUKH122, in the Orion A giant molecular cloud (GMC) in the CCS and ammonia (NH3) emission with the Very Large Array. TUKH122 contains one NH3 core “TUKH122- n,” which is elongated and has a smooth oval boundary. Where observed, the CCS emission surrounds the NH3 core. + This conﬁguration resembles that of the N2H and CCS distribution in the Taurus starless core L1544, a well-studied example of a dense prestellar core exhibiting infall motions. The linewidth of TUKH122-n is narrow (0.20 km s−1) in the NH3 emission line and therefore dominated by thermal motions. The smooth oval shape of the core boundary + and narrow linewidth in N2H seem to imply that TUKH122-n is dynamically relaxed and quiescent. TUKH122-n is similar to L1544 in the kinetic temperature (10 K), linear size (0.03 pc), and virial mass ( 2 M⊙). Our results strongly suggest that TUKH122-n is on the verge of star formation. TUKH122-n is embedded∼ in the 0.2 pc massive (virial mass 30 M⊙) turbulent parent core, while the L1544 NH core is embedded in the 0.2 pc less-massive (virial ∼ 3 mass 10 M⊙) thermal parent core. TUKH083 shows complicated distribution in NH3, but was not detected in CCS. The CCS∼ emission toward TUKH083 appears to be extended, and is resolved out in our interferometric observations. Accepted by Astrophysical Journal http://arxiv.org/pdf/1405.5286

ALMA observations of a high density core in Taurus: dynamical gas interaction at the possible site of a multiple star formation Kazuki Tokuda1, Toshikazu Onishi1, Kazuya Saigo2, Akiko Kawamura2, Yasuo Fukui3, Tomoaki Matsumoto4, Shu-ichiro Inutsuka3, Masahiro N. Machida5, Kengo Tomida6,7 and Kengo Tachihara3 1 Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan 2 National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan 3 Department of Physics, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan 4 Faculty of Humanity and Environment, Hosei University, Fujimi, Chiyoda-ku, Tokyo 102-8160, Japan 5 Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581, Japan 6 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA 7 Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan E-mail contact: s k.tokuda at p.s.osakafu-u.ac.jp Starless dense cores eventually collapse dynamically to form protostars in them, and the physical properties of the cores determine the nature of the forming protostars. We report ALMA observations of dust continuum emission and molecular rotational lines toward MC27 or L1521F, which is considered to be very close to a moment of the ﬁrst protostellar core phase. We found a few starless high-density cores, one of which has a very high density of sim107cm−3, within a region of several hundred AU around a very low luminosity protostar detected by the Spitzer. A very compact bipolar outﬂow with a dynamical time scale of a few hundred years was found toward the protostar. The molecular line observation shows several cores with arc-like structure, possibly due to the dynamical gas interaction. These complex structures revealed in the present observations suggest that the initial condition of star formation is highly dynamical in nature, which is considered to be a key factor to understand fundamental issues of star formation such as the formation of multiple stars and the origin of the initial mass function of stars. Accepted by Astrophysical Journal Letters http://arxiv.org/pdf/1405.7574

Core and ﬁlament formation in magnetized, self-gravitating isothermal layers. Sven Van Loo1, Eric Keto1 and Qizhou Zhang1 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA E-mail contact: svanloo at cfa.harvard.edu

38 We examine the role of the gravitational instability in an isothermal, self-gravitating layer threaded by magnetic fields on the formation of filaments and dense cores. Using numerical simulation we follow the non-linear evolution of a perturbed equilibrium layer. The linear evolution of such a layer is described in the analytic work of Nagai et al (1998). We find that filaments and dense cores form simultaneously. Depending on the initial magnetic field, the resulting filaments form either a spiderweb-like network (for weak magnetic fields) or a network of parallel filaments aligned perpendicular to the magnetic field lines (for strong magnetic fields). Although the filaments are radially collapsing, the density profile of their central region (up to the thermal scale height) can be approximated by a hydrodynamical equilibrium density structure. Thus, the magnetic field does not play a significant role in setting the density distribution of the filaments. The density distribution outside of the central region deviates from the equilibrium. The radial column density distribution is then flatter than the expected power law of r−4 and similar to filament profiles observed with Herschel. Our results does not explain the near constant filament width of 0.1pc. However, our model does not include turbulent motions. It is expected that accretion-driven amplification∼ of these turbulent motions provides additional support within the filaments against gravitational collapse. Finally, we interpret the filamentary network of the massive star forming complex G14.225-0.506 in terms of the gravitational instability model and find that the properties of the complex are consistent with being formed out of an unstable layer threaded by a strong, parallel magnetic field. Accepted by Astrophysical Journal http://arxiv.org/pdf/1405.1013

Accurate water maser positions from HOPS Andrew J. Walsh1, Cormac R. Purcell2, Steven N. Longmore3, Shari L. Breen4, James A. Green5, Lisa Harvey-Smith4, Christopher H. Jordan6 and Christopher MacPherson1 1 ICRAR/Curtin University 2 University of Sydney 3 Liverpool John Moores University 4 CSIRO Astronomy and Space Science 5 SKA Organisation 6 University of Tasmania E-mail contact: andrew.walsh at curtin.edu.au We report on high spatial resolution water maser observations, using the Australia Telescope Compact Array, towards water maser sites previously identified in the H2O southern Galactic Plane Survey (HOPS). Of the 540 masers identified in the single-dish observations of Walsh et al. (2011), we detect emission in all but 31 fields. We report on 2790 spectral features (maser spots), with brightnesses ranging from 0.06Jy to 576 Jy and with velocities ranging from 238.5 to +300.5km/s. These spectral features are grouped into 631 maser sites. We have compared the positions of these− sites to the literature to associate the sites with astrophysical objects. We identify 433 (69 per cent) with star formation, 121 (19 per cent) with evolved stars and 77 (12 per cent) as unknown. We find that maser sites associated with evolved stars tend to have more maser spots and have smaller angular sizes than those associated with star formation. We present evidence that maser sites associated with evolved stars show an increased likelihood of having a velocity range between 15 and 35km/s compared to other maser sites. Of the 31 non-detections, we conclude they were not detected due to intrinsic variability and confirm previous results showing that such variable masers tend to be weaker and have simpler spectra with fewer peaks. Accepted by MNRAS http://arxiv.org/pdf/1405.4096 The full preprint (718 pages, 21MB) can be downloaded from this http://www.hops.org.au under ”Publications”

Rapid Evolution of the Innermost Dust Disk of Protoplanetary Disks Surrounding Intermediate-mass Stars Chikako Yasui1, Naoto Kobayashi2, Alan T. Tokunaga3 and Masao Saito4,5 1 Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-

39 0033, Japan 2 Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan 3 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 4 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 5 Joint ALMA Observatory, Ave. Alonso de Cordova 3107, Vitacura, Santiago, Chile E-mail contact: ck.yasui at astron.s.u-tokyo.ac.jp

We derived the intermediate-mass ( 1.5–7 M⊙) disk fraction (IMDF) in the near-infrared JHK photometric bands as well as in the mid-infrared (MIR) bands≃ for young clusters in the age range of 0 to 10Myr. From the JHK IMDF, the lifetime of the innermost dust disk ( 0.3 AU; hereafter the K disk) is estimated to be∼ 3 Myr, suggesting a stellar mass ∼ −0.7 ∼ (M∗) dependence of K-disk lifetime M∗ . However, from the MIR IMDF, the lifetime of the inner disk ( 5 AU; ∝ −0.2∼ hereafter the MIR disk) is estimated to be 6.5Myr, suggesting a very weak stellar mass dependence ( M∗ ). The much shorter K-disk lifetime compared to∼ the MIR-disk lifetime for intermediate-mass (IM) stars suggests∝ that IM stars with transition disks, which have only MIR excess emission but no K-band excess emission, are more common than classical Herbig Ae/Be stars, which exhibit both. We suggest that this prominent early disappearance of the K disk for IM stars is due to dust settling/growth in the protoplanetary disk, and it could be one of the major reasons for the paucity of close-in planets around IM stars. Accepted by MNRAS http://arxiv.org/pdf/1405.5284v2.pdf

40 Abstracts of recently accepted major reviews

Exploring the Origins of Carbon in Terrestrial Worlds Edwin Bergin1, L. Ilsedore Cleeves1, Nathan Crockett2 and Geoffrey Blake2 1 University of Michigan, Department of Astronomy, 500 Church St., Ann Arbor, MI 48109 USA 2 California Institute of Technology, Division of Geological & Planetary Sciences, MS 150-21, Pasadena, CA 91125, USA E-mail contact: ebergin at umich.edu Given the central role of carbon in the chemistry of life, it is a fundamental question as to how carbon is supplied to the Earth, in what form and when. We provide an accounting of carbon found in solar system bodies, in particular a comparison between the organic content of meteorites and that in identified organics in the dense interstellar medium (ISM). Based on this accounting identified organics created by the chemistry of star formation could contain at most 15% of the organic carbon content in primitive meteorites and significantly less for cometary organics, which represent the∼ putative contributors to starting materials for the Earth. In the ISM 30% of the elemental carbon is found in −4 ∼ CO, either in the gas or ices, with a typical abundance of 10 (relative to H2). Recent observations of the TW Hya disk find that the gas phase abundance of CO is reduced by∼ an order of magnitude compared to this value. We explore a solution where the volatile CO is destroyed via a gas phase processes, providing an additional source of carbon for organic material to be incorporated into planetesimals and cometesimals. This chemical processing mechanism requires warm grains (> 20 K), partially ionized gas, and sufficiently small (agrain < 10 µm) grains, i.e. a larger total grain surface area, such that freeze-out is efficient. Under these conditions static (non-turbulent) chemical models predict that a large fraction of the carbon nominally sequestered in CO can be the source of carbon for a wide variety of organics that are present as ice coatings on the surfaces of warm pre-planetesimal dust grains. Accepted by Faraday Disc., 2014, Vol. 168, DOI: 10.1039/C4FD00003J http://arxiv.org/pdf/1405.7394

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41 Meetings

The Filamentary Structure in Molecular Clouds 10-11 October 2014 Charlottesville, Virginia, USA A North America ALMA Science Center (NAASC) Workshop

Filamentary structure in molecular clouds has been observed dating back many years. However, recent Herschel observations of nearby dust clouds have highlighted that the dense gas is distributed predominantly in filaments. It has been suggested that such filamentary structure may be ubiquitous in the internal structure of all molecular clouds and may be preferential formation sites of dense cores that eventually collapse to form stars. If such filamentary structures were universal in all molecular clouds of low mass and high mass star formation, then the whole paradigm of cloud formation and evolution leading to star formation would be placed on a more definitive framework that centers on cloud condensation into filaments and filament fragmentation into cores. This framework would focus the theoretical and observational studies of star formation in molecular clouds on the origin and evolution of dense filaments as one of the fundamental steps. This NAASC Workshop aims to bring together experts, postdoctoral fellows, and students, to discuss the current evidence for such a picture and to help formulate future projects on ALMA and other facilities - CARMA, SMA, SMT, GBT, VLA, JCMT, LMT, CCAT, etc. - and theoretical investigations to verify whether such filamentary structure is universal in molecular clouds in different environments and to study the physical conditions of such structures. A sample of outstanding issues to be addressed include: 1. Is filamentary structure in molecular clouds universal? 2. What are the kinematic characteristics of filaments and their local environment that would inform us on their origins? Do the filaments we observe arise from converging, super-Alfvenic gas flows, stretching and shearing of pre-existing features, or sub-Alfvenic flows along magnetic fields, and self-gravity? 3. How important is filamentary structure for star formation? Would the IMF be different if filaments were different? 4. What is the connection between the filamentary structure in molecular clouds and the shell-like structure of the HI medium? And, what is the relationship to the ionized regions? 5. What further observations would be needed to fully characterize the internal (filamentary) structure of molecular clouds in various environments? 6. The viability of similar studies of molecular clouds in the Magellanic Clouds, nearby Local Group galaxies and perhaps the nearest starburst galaxies, such as NGC253. Through this focused workshop, it is hoped that interested members of the community can formulate key projects on ALMA and other telescopes that will further define the internal structure of molecular clouds in various environments in the Galaxy. The workshop will take at NRAO in Charlottesville from 10-11 October 2014. Attendance will be limited to 60 participants. Further information will be made available at http://science/nrao.edu Science Organizing Committee: Fred Lo, Chair (NRAO), 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)

42 The Early Life of Stellar Clusters: Formation and Dynamics 3-7 November 2014, Copenhagen, Denmark http://www.nbia.dk/nbia-clusters-2014

The goal of the workshop is to bridge the artiﬁcial divide between the ﬁelds of star formation and stellar dynamics. Star formation provides the initial conditions for the long term evolution of stellar clusters, while the dynamics of stars in clusters after star formation has ceased can inform on the conditions that have prevailed in the environment in which the clusters have formed. The central topics of the workshop will thus focus on:

Reviewing the status of observations of star forming regions and young stellar clusters and discuss the prospects • with current and future ground based and space-borne telescopes Characterizing the dependence of the IMF, the SFE, binarity, sub-clustering, mass segregation, ages spreads on • the environment in which stars form Exploring the eﬀects of any variability in the outcome of the star formation process on the dynamical evolution • of stellar clusters Assessing the importance of the diﬀerent modes of stellar feedback and highlightng their importance on the • clusters SFE, dynamics, and survival Discussing the advances in the numerical modeling of star formation and the dynamical evolution of stellar • clusters and the necessity of having platforms that integrate all the required physics.

Workshop Organisers: Sami Dib (NBIA & StarPlan) Paolo Padoan (ICC, Barcelona) Simon Portegies Zwart (Leiden) Susanne Pfalzner (MPIfR, Bonn) Barabara Ercolano (USM, Munich) Inti Pelupessy (Leiden) Seyit H¨o¨uk (Groningen) Troels Haugblle (StarPlan & NBI)

43 Summary of Upcoming Meetings

The Submillimeter Array: First Decade of Discovery 9 - 10 June, 2014, Cambridge, MA, USA http://www.cfa.harvard.edu/sma/events/smaConf/ The 18th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun 9 - 13 June 2014 Flagstaﬀ, Arizona, USA http://www2.lowell.edu/workshops/coolstars18/ Summer School on Protoplanetary Disks: Theory and Modeling meet Observations 16 - 20 June 2014 Groningen, The Netherlands http://www.diana-project.com/summer-school Workshop on Dense Cores: Origin, Evolution, and Collapse 27 - 30 July 2014 Monterey, CA, USA http://www.aas.org/meetings/aastcs4 Characterizing Planetary Systems Across the HR Diagram 28 July - 1 August 2014 Inst. for Astronomy, Cambridge, USA http://www.ast.cam.ac.uk/meetings/2013/AcrossHR 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 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/ 45th “Saas-Fee Advanced Course”: From Protoplanetary Disks to Planet Formation 15-20 March 2015, Switzerland no website yet Other meetings: http://www1.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/meetings/