THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 260 — 14 August 2014 Editor: Bo Reipurth ([email protected]) List of Contents The Star Formation Newsletter Interview ...................................... 3 My Favorite Object ............................ 6 Editor: Bo Reipurth [email protected] Perspective ................................... 12 Technical Editor: Eli Bressert Abstracts of Newly Accepted Papers .......... 17 [email protected] Meetings ..................................... 56 Technical Assistant: Hsi-Wei Yen New and Upcoming Meetings ................. 58 [email protected] Short Announcements ........................ 59 Editorial Board Joao Alves Alan Boss Jerome Bouvier Cover Picture Lee Hartmann Thomas Henning The cover shows the W5-NE region, a bridge of Paul Ho molecular cloud separating the HII regions/clusters Jes Jorgensen W5-W (IC 1848) and W5-E (AFGL 4029). The im- Charles J. Lada age is about 12 × 14 arcmin, corresponding to ap- Thijs Kouwenhoven proximately 0.11 × 0.13 pc at the assumed distance Michael R. Meyer of 1.95 kpc. The bright star at the center of the im- Ralph Pudritz age is BD +60◦596, a B1V star which has created Luis Felipe Rodr´ıguez the cavity seen in the image. Numerous young low- Ewine van Dishoeck mass stars are found in this region, including the Hans Zinnecker young variable LW Cas. East is up and north is right in this image. The Star Formation Newsletter is a vehicle for fast distribution of information of interest for as- Image courtesy Ken Crawford http://www.imagingdeepsky.com tronomers working on star and planet formation ( ) and molecular clouds. You can submit material for the following sections: Abstracts of recently accepted papers (only for papers sent to refereed journals), Abstracts of recently accepted major re- views (not standard conference contributions), Dis- sertation Abstracts (presenting abstracts of new Submitting your abstracts Ph.D dissertations), Meetings (announcing meet- ings broadly of interest to the star and planet for- Latex macros for submitting abstracts mation and early solar system community), New and dissertation abstracts (by e-mail to Jobs (advertising jobs specifically aimed towards [email protected]) are appended to persons within the areas of the Newsletter), and each Call for Abstracts. You can also Short Announcements (where you can inform or re- submit via the Newsletter web inter- quest information from the community). Addition- face at http://www2.ifa.hawaii.edu/star- ally, the Newsletter brings short overview articles formation/index.cfm on objects of special interest, physical processes or theoretical results, the early solar system, as well as occasional interviews. Newsletter Archive www.ifa.hawaii.edu/users/reipurth/newsletter.htm 2 the launch of IRAS. So we missed out on jets/disk winds, though I think our paper did provide some motivation for Lee Hartmann the X-wind model of Frank Shu and his collaborators. in conversation with Bo Reipurth The Alfven wave-driven wind models were also motivated by the need to produce massive flows in the absence of sig- nificant thermal and radiative driving, but in this case the stars were known to be slowly rotating, so we had to in- voke high-frequency, turbulently-produced waves. Work- ing first with Suzan Edwards and Gene Avrett, and then later with Nuria Calvet in the context of schematic disk winds, we could get emission line ratios fairly well, but the line profiles generally didn’t match the observations. Then in 1989 I was visiting Santa Cruz and mentioned the problem of the slow rotation of T Tauri stars to Doug Lin. Doug suggested that the slow rotation was a result of magnetospheric coupling which transferred excess stel- lar angular momentum to the disk. Cluelessly, I dismissed this idea because I thought making a magnetospheric hole in the disk should produce a gap in the near-IR infrared Q: Your early papers had nothing to do with young stars. spectral energy distribution that was not apparent... just How did you develop your interest in star formation? before Arieh K¨onigl’s paper came out on magnetospheric A: My early years were really kind of a random walk braking. (My mistake was to ignore emission from the through (mostly) stellar astrophysics. I worry a bit now directly-illuminated, hotter inner “wall” of the dust disk, about young people who don’t have the opportunity to which fills in the short-wavelength SED, as shown by An- try out different things until they find the subject that’s tonella Natta and collaborators.) I went back to Nuria best for them. Anyway, I had originally been working on and said, we’ve gotten this all wrong; we should be doing the theory of extended stellar atmospheres and winds as a models of (magnetospheric) infall, not outflow. Making grad student with Joe Cassinelli at Wisconsin, but decided this change resulted in very good agreement with many I needed some observational experience and worked with line profile observations, as ultimately developed in some Chris Anderson on spectra of flare stars. The resulting detail in James Muzerolle’s thesis work. thesis wasn’t very good but it introduced me to solar-type Q: Your first venture into observations of young stars magnetic activity. came with your 1982 paper on high resolution spectroscopy Then I went to CfA as a postdoc and began working with of T Tauri stars. Another large observational effort was Andrea Dupree on International Ultraviolet Explorer satel- your study of rotational and radial velocities of T Tauri lite observations of all kinds of objects - globular clusters, stars. What motivated you to embark on observations? X-ray binaries, cataclysmic variables, you name it, along A: New detectors became available at Mt. Hopkins, ver- with John Raymond. My major focus eventually became sions of the intensified Reticon developed by Steve Schecht- chromospheric and coronal emission of solar-type stars, man. The Reticons were solid-state 2 x 1024 pixel arrays, which then led to my interest in T Tauri stars, which kind of forerunners of CCDs, but had huge read noise. To were supposed to be the most magnetically-active late- get around that problem, the Reticon was placed at the type stars... but that isn’t the big story. back end of a collection of image tubes (pause for young Q: In the early 1980s you wrote a series of highly influen- readers, if any, to google the term), which turned each in- tial papers with MacGregor on wave-driven winds. coming photon into a huge spray at the Reticon, defeating the read noise and allowing one to count individual pho- A: Keith had worked on rotating, magnetized solar-type tons. It was a huge improvement over what we had before, wind models for his thesis, and applied these to the very not only because of increased sensitivity but because the massive outflow in Orion-KL, showing that a magnetized data went straight into the computer without the need to protostellar cloud rotating at breakup could drive a mas- scan plates. I figured it would be useful to have a kind sive wind. But we did this for equatorial flow; at roughly of album of T Tauri line profiles using this new device. the same time the Blandford and Payne and Pudritz and In particular, I remember an Hγ profile of DF Tau where Norman papers came out on disk winds/jets driven by it showed simultaneous red- and blue-shifted absorption, magnetic fields anchored in the rotating disk. The im- and puzzling over it. Of course now we can interpret this portance of disks only became clear somewhat later with as magnetospheric infall interior to an expanding wind. 3 I think my interest in making a survey of rotation in T the infrared spectrum. As far as I know, the most compre- Tauri stars stemmed from my collaboration with John hensive comparison of a detailed SED with a steady disk Stauffer, who was leading efforts to study the subset of model for any astrophysical object is for FU Ori; as shown rapidly-rotating solar-type stars in the Pleiades. Prob- in the right panel of Figure 1 of arXiv:1106.3343, we can ably the idea was to see how initial angular momenta fit the observations over a factor of 30 in wavelength in- mapped into the Pleiades rotation allowing for contrac- cluding the absorption bands in the near- to mid-infrared. tion to the main sequence and seeing how much angular Zhaohuan Zhu, Catherine Espaillat, Ken Hinkle and I also momentum loss via winds one needed. Along with Jerome showed that the differential rotational velocities remain Bouvier’s simultaneous study, we showed the slow T Tauri consistent with Keplerian out to 4.6µm. No other model rotation more systematically than had been done before. explains all these results. (Although magnetospheric braking probably is responsi- Modeling the optical spectral lines accurately involves sev- ble for the slow rotation, exactly how it works still puz- eral subtleties, such as accounting for the non-power-law zles me.) On a personal note, it engendered about the temperature distribution of the inner disk, and in the case worst referee report I’ve ever gotten, with 70 paragraphs of FU Ori, correcting for the Doppler shifts of the emerging (I counted) of scathing criticism. I was ready to jump off disk wind. That said, the mechanism(s) of the outbursts a bridge until I received a very nice letter from George still remain unclear. Perhaps the ongoing discovery and Herbig, who liked the paper. That meant a lot to me. characterization of the weaker EXor outbursts will help. Q: In 1985 came your paper with Scott Kenyon on the na- Q: Your most cited first-author paper, together with Nuria ture of FU Orionis objects, followed by a series of studies Calvet and collaborators, is the 1998 study ′Accretion and of FUors, and culminating in your Annual Reviews article the Evolution of T Tauri Disks′.