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257 — 10 May 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. 257 — 10 May 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 ................................... 10 Technical Editor: Eli Bressert Abstracts of Newly Accepted Papers .......... 14 [email protected] Abstracts of Newly Accepted Major Reviews . 42 Technical Assistant: Hsi-Wei Yen New Jobs ..................................... 44 [email protected] New and Upcoming Meetings ................. 45 Editorial Board New Books ................................... 47 Passings ...................................... 48 Joao Alves Alan Boss Short Announcements ........................ 49 Jerome Bouvier Lee Hartmann Thomas Henning Paul Ho Jes Jorgensen Cover Picture Charles J. Lada Thijs Kouwenhoven This image shows the LBN 777 nebula in Tau- Michael R. Meyer rus close to the Pleiades. The cloud was origi- Ralph Pudritz nally catalogued as Barnard 207, and has later be- Luis Felipe Rodr´ıguez come known as L1489. It contains the protostar Ewine van Dishoeck IRAS 04016+2610, a small multiple system that Hans Zinnecker produces a molecular outflow and a chain of HH objects 360, 361, 362. The cometary shape of the The Star Formation Newsletter is a vehicle for globule suggests that the star formation event may fast distribution of information of interest for as- have been triggered by an external event. tronomers working on star and planet formation and molecular clouds. You can submit material Image courtesy Mark Hanson for the following sections: Abstracts of recently http://www.btlguce.com 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- ings 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 in the control room, where people jumped and shouted when they viewed the screen with spectra never seen be- G¨osta Gahm fore. So did I when I saw the spectrum of RU Lupi. in conversation with Bo Reipurth We thought the strong emission lines from hot regions im- plied TTS chromospheres enhanced by factors 105 com- pared to the sun. The concept of magnetospheric accretion from circumstellar disks had not yet emerged. Fascinat- ing how our view of the T Tauri phenomenon has changed since then. And can RU Lupi still hide some secrets? Over the last years, my main partners on TTS have been Peter Petrov, Eric Stempels, Fred Walter, and Gregory Herczeg, and in our last paper (2013) we found evidence that the ac- cretion streams are curved and trailing the star. If con- firmed, I think an exciting step will be to match observed spectral variations with line transfer calculations based on recent models involving complex, non-axisymmetric mag- netic field configurations. Q: In 1970, you were the first astronomer in Scandinavia Q: You did one of the pioneering studies of T Tauri stars to study young stars. From where came the inspiration? in X-rays using Einstein. Do your early conclusions still stand in light of what we have learnt from later missions? A: It all started after my supervisor Per Olof Lindblad arranged a stay with George Herbig at the Lick Obser- A: After the first FUV surveys the next natural step was vatory. George gave me a coud´espectrum of RW Aur A to explore how TTS appear at higher energies. Timely, the and suggested I should think of something one could learn X-ray satellite Einstein was launched. There were predic- from it. I started to read all I could find about T Tauri tions around on high X-ray fluxes based on extrapolations stars (TTS) in the library. After a month we met again. of the strong ”hot” lines found in the FUV. I selected a I had many questions but he insisted on asking me what number of such stars and got so astonished when I found I thought. He was a wonderful mentor. that none was detected in X-rays. By chance, one field in- cluded a weak-line TTS, and yes, this object had a strong When back in Stockholm after a year and half at Lick I signal. When closing a paper on this (1980) I realized that was hooked on young stars, and people said I was talk- at these relatively low X-ray energies the bulk of the X-ray ing only about TTS during breakfast, lunch and dinner. emission can be absorbed in the gas surrounding the stars. Despite this some students thought the subject was excit- I added a note on this at the last moment. ing. A group expanded including G¨oran Olofsson, Lennart Nordh, Ren´eLiseau, Peter Lindroos, Malcolm Fridlund, Since then X-ray observations have provided a wealth of and Erik Gullbring, some of whom are still active in as- data with information on stellar coronae, accretion shocks, tronomy. stellar flares and also shock-excited regions further out from the star, like Herbig-Haro objects. I did not continue Q: You have been studying RU Lupi for many years, in- myself within this field, except that we have collected X- cluding the first far-ultraviolet study. Does RU Lupi still ray data during periods of groundbased monitoring. It was surprise? always hard to arrange strictly simultaneous X-ray and A: After Lick we started simultaneous spectroscopic and optical observations, but now we have seen such studies photometric observations at ESO, which was still in its appearing in the literature. pioneering phase. Our first target was RU Lupi, a TTS Q: You and your collaborators have found evidence that with an extremely rich emission line spectrum. I have RW Aur A may be a spectroscopic binary. Has this been returned many times to this star as well as to RW Aur further supported by additional data? A. Not unusual that astronomers return to the place of the crime, I have found. Each time we gained some new A: There was indeed a time when I thought the small- insights, but new questions always popped up. amplitude periodic velocity changes we detected in TTS could flag the presence of brown dwarfs in close orbits, and At the time new spectral windows became accessible for which would eventually be swallowed by the star. It could studies of TTS. Observers from all parts of Europe gath- also explain how non-axisymmetric accretion streams de- ered in Villafranca, Spain to conduct FUV observations velop in their combined magnetospheres. I was arguing with the IUE satellite. I remember many exiting moments with Petrov, who thought we instead were dealing with 3 two accretion areas not aligned with the stellar rotation magnetic forces, which was partly true. Per Carlqvist ar- axis. Colleagues called our conversations quarrels, and I gued that plasma physics should be applied in full scale remember how we spent a whole evening in the dancing in models of interstellar clouds. Even the cold molecu- hall on a ferry between Stockholm and Helsinki totally oc- lar clouds are by standard definitions plasmas. We stud- cupied by finding the weak points in each story and ways ied twisted, filamentary clouds in CO with collegues in to defend our own conclusions. In fact, quarrels can be Finland and Onsala, Anlaug Kaas and P¨aivi Harjunp¨a¨a very refreshing and creative. We finally presented both mapped polarization, and with Helmuth Kristen we sur- views in a paper on RW Aur A (2001). veyed elephant trunks in 10 H II regions in Hα at the Later, when investigating the same phenomenon in RU Nordic Optical Telescope. Lupi, I had to admit that Peter probably was on the right We found that many trunks are composed of thin molecu- track after all. The periodic velocity changes are related to lar threads that can be confined over parsecs. Several look cold and hot spots on the rotating star. Usually we agree like twisted coaxial cables and shaped like double helices in on how to interpret observations, and our collaboration some cases. Not far-fetched to think that electromagnetic has always survived since we met in Moscow back in 1974. forces play an important role in sculpting these features. As the Swedish poet Nils Ferlin wrote: God may forgive Carlqvist developed the ”Theory of twisted trunks”. me certain lines. However, one must check each star care- Magnetic fields and electric currents are here to stay, and fully. Recently, K´osp´al et al. found that in EX Lup such over the last decade some very impressive models have velocity variations are caused by a close component. been published treating the evolution of ”magnetic” shells Q: You had the interesting idea to look for young binaries and trunks in H II regions. pairing OB stars with T Tauri stars, and found a number Q: Your latest interest are the small ”globulettes” in HII of such cases, work later continued by Peter Lindroos.
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