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THE STAR FORMATION NEWSLETTER an Electronic Publication Dedicated to Early Stellar/Planetary Evolution and Molecular Clouds No THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 266 — 12 February 2015 Editor: Bo Reipurth ([email protected]) List of Contents The Star Formation Newsletter Interview ...................................... 3 My Favorite Object ............................ 6 Editor: Bo Reipurth [email protected] Abstracts of Newly Accepted Papers .......... 12 Technical Editor: Eli Bressert Abstracts of Newly Accepted Major Reviews . 49 [email protected] New Jobs ..................................... 50 Technical Assistant: Hsi-Wei Yen Meetings ..................................... 52 [email protected] Summary of Upcoming Meetings ............. 58 Editorial Board Joao Alves Alan Boss Jerome Bouvier Cover Picture Lee Hartmann Thomas Henning The cover shows an HST ACS image of the neb- Paul Ho ulous star LkHα 326, a young binary surrounded Jes Jorgensen by a bright reflection nebula in the lower part of Charles J. Lada the image. Towards the top is the much fainter Thijs Kouwenhoven young star SSTc2d J033038.2+303212, which dis- Michael R. Meyer plays an edge-on disk and a tiny jet, oriented along Ralph Pudritz the ’chimney’ emanating from the star, apparently Luis Felipe Rodr´ıguez outlining an outflow lobe. Both stars are part of Ewine van Dishoeck a little aggregate of young low-mass stars, dubbed Hans Zinnecker ’Per 6’ in Rebull et al. (2007), and located in the small dark cloud Dobashi 4173 in the constellation The Star Formation Newsletter is a vehicle for Perseus. North is approximately down and east ap- fast distribution of information of interest for as- proximately left. tronomers working on star and planet formation and molecular clouds. You can submit material Image credit ESA/NASA. 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 Ph.D dissertations), Meetings (announcing meet- Submitting your abstracts ings broadly of interest to the star and planet for- mation and early solar system community), New Latex macros for submitting abstracts Jobs (advertising jobs specifically aimed towards and dissertation abstracts (by e-mail to persons within the areas of the Newsletter), and [email protected]) are appended to Short Announcements (where you can inform or re- each Call for Abstracts. You can also quest information from the community). Addition- submit via the Newsletter web inter- ally, the Newsletter brings short overview articles face at http://www2.ifa.hawaii.edu/star- on objects of special interest, physical processes or formation/index.cfm theoretical results, the early solar system, as well as occasional interviews. Newsletter Archive www.ifa.hawaii.edu/users/reipurth/newsletter.htm 2 large projects or, for that matter, any project that did not involve the discovery of a new molecular species. To rem- Charlie Lada edy this, an informal consortium of Bell Labs, Harvard, in conversation with Bo Reipurth Columbia and Texas got together to build a millimeter- wave observatory (MWO) using an existing NASA dish at the McDonald Observatory. The members evenly split the observing time. The Harvard group was primarily in- terested in discovering new molecular species while I was solely interested in astronomical mapping and surveying. The telescope was not optimized for molecular searches and that line of work turned out not to be that productive. But the MWO was a terrific survey telescope for mm-wave lines. As a consequence between 1973 and 1978 I was able to use most of the Harvard time to map molecular clouds. Two to three times a year I traveled to McDonald for two-week long runs, observing around the clock. It was exhausting but it paid high dividends! It was the most exciting time of my career. Imagine, no observing propos- Q: Your PhD thesis in 1975 dealt with some of the first als, no TACs to deal with, just show up at the telescope, observations of molecular clouds. What was at that time exploit hot new technology and do interesting new science. the context for your thesis research? Q: Nearly 40 yrs ago at IAU Symp 75 in Geneva you and A: When I started on my thesis work in 1973, molecules Bruce Elmegreen presented your model of sequential star were just beginning to be detected in emission in inter- formation. What was the genesis of this influential idea? stellar space. Most of the effort in those days was toward A: I was very influenced by the Annual Reviews article of discovering new molecular species. Not much was known Adriaan Blaauw on OB associations. In my thesis work about individual clouds themselves. The paradigm then on M17 and M8, I noticed that there was possibly a natu- was that molecular clouds were impurities within or, at ral extension of Blaauw’s age sequence of association sub- most, exotic appendages to HII regions. Since HII regions groups into molecular clouds. Shortly after I started my were acknowledged signposts of star formation, I guessed postdoc at the CfA I met with George Field and asked if that molecules might be important for star formation. I he or someone in his group would be interested in work- got the idea to try to determine the actual physical connec- ing with me to develop a theoretical framework for this tion between molecular and ionized gas within HII regions. idea. He sent me to Bruce Elmegreen, a recently arrived I think that one of the contributions of my thesis work was Junior Fellow at Harvard. I remember going to Bruce’s to reverse the existing paradigm by providing some of the office and outlining the observations that suggested trig- first evidence that molecular clouds were truly enormous, gering of star formation in M17, M8 and Orion and its rivaling OB associations in size and that HII regions were possible connection to Blaauw’s subgroups. I walked out in fact mere appendages to molecular clouds! Also the re- of Bruce’s office in a daze. Within two hours, sitting in sults of my thesis suggested that the diverse and seemingly front of me, he flushed out the bones of a complete the- unrelated signposts of star formation, such as OB and T oretical framework! Of course it took a few months to associations, HII regions, masers, HH objects, IR proto- put the flesh on those bones, but by the time of the first stars, etc., had one fundamental thing in common, they IAU Symposium on star formation in 1976 we had pretty all were physically associated with cold, massive, molec- much completed the work. I marshaled the observational ular clouds. This insight then led me to the notion that evidence, Bruce worked out the theoretical details–it was a these apparently disparate phenomena might actually be very effective and complementary scientific collaboration! manifestations of different evolutionary stages in a regular The symposium was exciting, as many of the giants of the star formation process operating within molecular gas. field such as Bok, Spitzer, Herbig and Larson were in at- Q: How did you get involved with millimeter-wave obser- tendance. And the most amazing part was that Blaauw vations that at the time were so very new ? was also there and was most encouraging about our work. A: I was very lucky to be in the right place at the right Q: Almost 30 yrs ago, at the IAU Symposium 115 in time. In the mid seventies there were only two telescopes Tokyo, you introduced the Class system for young stel- in the world that could observe CO: the NRAO 36-ft on lar objects, which has now become a fixture in our view of Kitt Peak and the 16-ft at McDonald Observatory. It was early stellar evolution. How did that originate? essentially impossible to get sufficient time at NRAO for A: That came about when I was in Arizona. My first grad- 3 uate student, Bruce Wilking, had just completed his thesis quent highly cited ARAA review on molecular outflows. work on the infrared cluster embedded in the ρ Ophiuchi What are your reminiscences from those early efforts? cloud. He discovered many new and deeply embedded A: This story began for me at the MWO in the fall of members of the cluster. At the time the physical natures 1978 when Paul Harvey and I discovered extremely high of such infrared sources were unclear. Were they reddened velocity wings in the CO line toward the luminous infrared young OB stars, or some kind of mysterious young objects source AFGL 490. At that time only the famous Orion KL of unknown physical nature? We decided that to best source was known to exhibit such high velocity CO. Its address this question we needed to extend Bruce’s obser- origin was somewhat of a mystery with much speculation vations to longer wavelengths and obtain more complete about an embedded supernova as a possible cause. Unlike SEDs. We obtained 10µm observations of a large sample Orion, the high velocity gas in AFGL 490 appeared to be of these sources using the IRTF on Mauna Kea. When I partially resolved with the Texas antenna. Realizing that constructed their SEDs I noticed that they could be clas- resolved observations would provide critical constraints on sified by shape into three distinct groupings in what ap- the energetics and dynamics of the high velocity gas, we peared to be a progressive sequence of increasing circum- used the larger NRAO 11m telescope to obtain maps of stellar extinction. If I had read Lynden-Bell and Pringle, the source. I assigned an undergraduate student, Frank I would have instantly recognized that one of the SED Taylor, to work on the data and construct a spatial map groups (Class II) had the telltale signature of circumstel- of the emission in the line wings.
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