THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 248 — 11 August 2013 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 .......... 10 Technical Editor: Eli Bressert Dissertation Abstracts ........................ 44 [email protected] Meetings ..................................... 45 Technical Assistant: Hsi-Wei Yen Meetings of Possible Interest .................. 47 [email protected] Editorial Board Joao Alves Alan Boss Cover Picture Jerome Bouvier Lee Hartmann The image, obtained with the Hubble Space Tele- Thomas Henning scope, shows photoevaporating globules embedded Paul Ho in the Carina Nebula. Jes Jorgensen Charles J. Lada Image courtesy NASA, ESA, N. Smith (University Thijs Kouwenhoven of California, Berkeley), and The Hubble Heritage Michael R. Meyer Team (STScI/AURA) Ralph Pudritz Luis Felipe Rodr´ıguez Ewine van Dishoeck Hans Zinnecker The Star Formation Newsletter is a vehicle for Submitting your abstracts fast distribution of information of interest for as- tronomers working on star and planet formation Latex macros for submitting abstracts and molecular clouds. You can submit material and dissertation abstracts (by e-mail to for the following sections: Abstracts of recently [email protected]) are appended to each accepted papers (only for papers sent to refereed Call for Abstracts. You can also submit via the journals), Abstracts of recently accepted major re- Newsletter web interface at http://www2.ifa. views (not standard conference contributions), Dis- hawaii.edu/star-formation/index.cfm sertation Abstracts (presenting abstracts of new Ph.D dissertations), Meetings (announcing meet- ings broadly of interest to the star and planet for- mation and early solar system community), New Jobs (advertising jobs specifically aimed towards persons within the areas of the Newsletter), and Short Announcements (where you can inform or re- quest information from the community). Addition- ally, the Newsletter brings short overview articles 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 ficult, was to give up my tenure track position and go to the University of California at Berkeley on a second post- David Hollenbach doc, essentially, to pursue research. I loved the people in in conversation with Bo Reipurth the astronomy department there, and they were incredi- bly supportive to me, especially Chris McKee, with whom I have had a lifelong collaboration and friendship. Even- tually, in 1980, I got my permanent position at NASA Ames, but maintained ties to UC Berkeley. My teaching experience actually gave me a much better foundation on which to do research, and I found that I loved research and working one on one with graduate students and postdocs, rather than teaching large classes. I might say, also, that a 1977 workshop in Erice, Italy on infrared astronomy had a profound influence on my career. I left really feeling that infrared astronomy was going to be very exciting in the coming decades, and decided to focus my research on areas relevant to infrared astronomy. That ultimately led to my being hired at NASA Ames, since IR astronomy was one of its key areas with the Kuiper Air- borne Observatory, and its involvement in IRAS, SIRTF Q: You had a slow start to your research career? Was that (Spitzer), and LDR (this idea eventually ended up as Her- circumstances or choice? schel). I also met a graduate student, Xander Tielens, in A: It was a combination of the two. The circumstances Erice, and he became my first postdoc at NASA Ames af- were these. I was from a small, conservative town in west- ter he graduated from Leiden. It was, as you say, a slow ern Michigan, and left that area to do my PhD at Cornell start, filled with much anxiety, but very interesting and in 1964. I then left Cornell to do a postdoc at Harvard rewarding. Luck and relationships had a lot to do with it. in 1968. For those too young to experience those years, Q: Your two first papers, from 1971, dealt with the role of let me say they were intense and, for me, life changing grains in the formation of molecular hydrogen, and they and mind changing. There was ”the War”, civil rights and have had a major influence on the subject. How have your black power, women’s liberation, and major changes in the results held up 40+ years hence? way you thought about relationships, religion, politics, the environment, music, drugs, dress and work. By the time A: Of course, I am prejudiced, but I think they have held I got to Harvard, I was very alienated from the status up quite well. One of the key issues then and now is that, quo. It seemed that academia was a competitive game on a pure surface with weak van der Waal forces dominat- compared to the issues of the military industrial complex, ing and no enhanced binding sites, the hydrogen atoms the devastation of the environment, the oppression of mi- would evaporate (sublimate) before finding each other to norities and women, the complicity of the media, and the form a molecule if the grain temperature was more than isolation of the individual consumer in ”established” soci- about 10-20 K. Such results were found in the laboratory ety. So I wasted two years at Harvard, and worked mainly in the 80’s and 90’s by Vidali, Pirronello and their cowork- with a group of folks starting one of the first organic food ers. However, there could be sites where at least partial stores and restaurants in Cambridge. My wife and I then chemical bonds held the atomic hydrogen, so that it would left to join the commune which provided much of the or- not evaporate from the surface. In our 1971 paper, we al- ganic food on a farm in Vermont. lowed for this by having what we called ”impurity sites”, although the number of them was a free parameter. The choices were these. I had an epiphany in Vermont. My wife and I were starved for intellectual stimulation. On the theoretical front, there has been much elaboration The thought came to me that one should make the most lately of this idea, by Cazaux and Tielens, and by Cuppen of one’s abilities in the world. So I chose to return to et al. These studies indicate that even at grain tempera- academia, and was lucky (jobs were very scarce then, as tures as high as 100 K, the formation rates of molecular they are now) to get physics and astronomy teaching jobs hydrogen may only be down roughly an order of magni- in Colorado from 1971 to 1975. I had gone to graduate tude from their low temperature rates. school thinking I would be a college teacher, like my fa- On the observational front, it is clear that in PDRs with ther, so I returned to that vision. However, I discovered nearby massive stars the grains are heated to at least 50 K that I had too much ”stage fright” to be in front of class and still the molecular hydrogen is forming quite efficiently after class. So my second choice, which was even more dif- 3 on their surfaces (Habart et al had a nice paper on this faces, and potential chemical reactions of these elements in 2004). Interstellar grain surfaces are likely so complex on the grain surfaces. My own group has been working that, at this point, I favor this approach of observing PDRs hard on this problem, and so have a number of PDR mod- and inferring the rates of molecular hydrogen formation as elers in Europe and the US. Observationally, one of the a function of grain temperature by matching observations key stimulants to this work has been the observed low with PDR models. abundance of gas phase water and molecular oxygen (seen by SWAS, Odin and Herschel, for example), as well as re- Q: Your most cited work is the series of papers on molecule + + cent observations of molecular ions like OH , H2O , and formation and infrared emission in fast interstellar shocks + together with Chris McKee. When you worked on this, did H3O . you realize that this would have such a profound impact in Another thing that comes to mind is the possible role of the community? turbulence in PDRs, stressed especially by Falgarone and A: I got interested in shock waves through my friend Dick her collaborators, in heating the gas and modifying the McCray, who had worked on the expansion of wind-driven chemistry. PDR models sometimes seem to lack sufficient bubbles in the ISM. He called the ISM ”violent”, and that heating to explain the observations of, for example, mid J impressed me. When I got to Berkeley, there had been CO transitions or pure rotational H2 transitions. In a way, some observations of vibrational emission of molecular hy- this is like a model which combines shocks and PDRs. drogen in Orion by Treffers, Gautier and Larson, and Steve Q: Your latest paper is on interstellar H2O masers. How Beckwith and coworkers also observed it around this time. have your thoughts on such masers evolved since you first Mike Shull was visiting Berkeley and he and I worked on began work on this 20 years ago? shock models of this emission. That was the start. Then, I A: There have been considerably more observations in the started working with Chris and we went much more deeply past 20 years that give evidence that water masers are into shocks, expanding the velocity range of the shocks often connected with shocks, especially shocks driven by and the postshock chemistry and infrared emission.