THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar/planetary evolution and molecular clouds No. 316 — 20 April 2018 Editor: Bo Reipurth ([email protected]) List of Contents The Star Formation Newsletter Interview ...................................... 3 My Favorite Object ............................ 5 Editor: Bo Reipurth [email protected] Abstracts of Newly Accepted Papers .......... 10 Associate Editor: Anna McLeod Meetings ..................................... 44 [email protected] Summary of Upcoming Meetings ............. 48 Technical Editor: Hsi-Wei Yen Short Announcements ........................ 50 [email protected] Editorial Board Joao Alves Cover Picture Alan Boss Jerome Bouvier CG 4 belongs to the system of cometary globules Lee Hartmann that are found in the Gum Nebula and pointing to- Thomas Henning wards the massive stars γ Vel and ζ Pup. These Paul Ho globules represent former cloud cores, which have Jes Jorgensen been escavated from their more tenous parental Charles J. Lada clouds. The globules are associated with 2. gen- Thijs Kouwenhoven eration low-mass star formation triggered by the Michael R. Meyer expanding HII region and radiation pressure. Im- Ralph Pudritz age obtained with ESO’s Very Large Telescope. Luis Felipe Rodr´ıguez Ewine van Dishoeck Image courtesy ESO Hans Zinnecker The Star Formation Newsletter is a vehicle for fast distribution of information of interest for as- tronomers working on star and planet formation and molecular clouds. You can submit material Submitting your abstracts for the following sections: Abstracts of recently accepted papers (only for papers sent to refereed Latex macros for submitting abstracts journals), Abstracts of recently accepted major re- and dissertation abstracts (by e-mail to views (not standard conference contributions), Dis- [email protected]) are appended to sertation Abstracts (presenting abstracts of new each Call for Abstracts. You can also Ph.D dissertations), Meetings (announcing meet- submit via the Newsletter web inter- ings broadly of interest to the star and planet for- face at http://www2.ifa.hawaii.edu/star- mation and early solar system community), New formation/index.cfm 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 Q; In 1993 came the famouns paper by Philippe Andr´e, yourself, and Mary Barsony on Class 0 sources. What Derek Ward-Thompson was the genesis of that paper? in conversation with Bo Reipurth A: The genesis of the Class 0 paper was actually very in- teresting. Philippe had been working with radio data of Ophiuchus and found a point source apparently just to one side of Oph A, which had the VLA catalogue name of VLA1623. He read my Oph A paper and wanted to know whether I had detected VLA1623 in any of my data. It could still have been a background radio galaxy at that point. So he wrote me an old-fashioned letter! Inter- national email was still in its infancy at that time and was very flaky. We eventually managed to make contact electronically and we realised that the UKIRT data were too low resolution to definitively say whether VLA1623 had been detected. So we agreed to write a telescope proposal for the still relatively new James Clerk Maxwell Telescope in Hawaii, where the single pixel bolometer had Q; What was your PhD about and who was your adviser? been moved to. Philippe had met Mary at a conference, A: My PhD was actually on the topic of magnetic fields and she had also expressed an interest in Ophiuchus, so in spiral galaxies. I worked with Mike Scarrott in the the three of us wrote the proposal together and went ob- Durham Polarimetry Group, so I’ve always been inter- serving together. When we took the data we realised what ested in polarimetry and magnetic fields. However, after we had found – a very bright point source in the submil- my PhD I decided that I wanted to look at objects that limetre that was by then known to have an energetic CO are a bit closer to home, so I decided to concentrate on outflow that had to be a young stellar object – but it was regions of star formation. At the time the IRAS data were invisible in the infra-red! At the time the YSO classifica- still relatively new, and I was determined to make images tion system of Class I, II & III had just been proposed. from the IRAS time-stream data. In fact, I was part of the But it was clear that this object had to be more embedded vanguard of folk making images from IRAS data (some- (i.e. younger) than a Class I. We realised we had discov- thing the satellite was never originally intended to do), ered a whole new class of objects that were not previously and ultimately this was taken up by IPAC on an indus- known! Philippe said, almost as a joke, that we should trial scale. Now the IRAS all-sky data are amongst the call the new class of objects Class 0. I remembered my prettiest pictures in infra-red astronomy. classical education and knew that there was no Roman numeral zero, and so I agreed to this name straight away, You were among the first to use submillimetre obser- Q; because I thought that it would make my old school Latin vations of star forming regions. In 1989 you and your co- teacher turn in his grave! And so it was decided – before workers discovered the famous submillimetre source SM1 we had even left the telescope control room. When we re- in Oph A. What is known about this source today? ρ turned to sea level we drank champagne in the then Joint A: For my first post-doc I worked with Ian Robson (who Astronomy Centre kitchen. We knew the paper that we subsequently became JCMT Director), when the newest planned to write would make a splash. telescope opening up new windows was the JCMT, so I Q; Another highly cited paper from around the same time jumped at the chance to use it. Continuum bolometer dealt with submm observations of ‘star-less’ cores. What detectors were becoming sensitive enough to see some- were your key conclusions? thing, so we tested out a single-pixel bolometer at UKIRT – pointing it at ρ Oph A. We made the first continuum A: After VLA1623, I began to wonder if there was any- image (built up point by point) of ρ Oph A and detected thing younger that we could see with our new-found sub- a bright source which we named SM1 (sub-millimetre 1) millimetre continuum sensitivity. At the time Phil My- for the first detected sub-millimetre continuum source in ers and co-workers had mapped a number of Lynds Dark Oph A. Many people have referred to SM1 without ever Clouds in CO and ammonia, and had cross-referenced this understanding why we called it that! Now we know far with the IRAS point source catalogue, which detected all more about this source. We know that it contains mul- Class I, II & III sources. So I proposed to point the JCMT tiple sub-clumps, it is part of a shell around the S1 HII at a large number of clouds that had ammonia detections region, and we even know what its magnetic field looks like but no IRAS point sources to see what we could see. Be- from SCUBA2 polarimeter and SOFIA HAWC+ data. cause of the mismatch in resolution I didn’t know exactly 3 where to point the JCMT within the ammonia cores (there Q; With the launch of the Herschel Space Telescope, a new was still only one pixel in our camera), so I hit on the idea tool became available for the study of star formation. How of mapping the cores in 13CO (which was quicker than do Herschel and SCUBA-2 compare? mapping in the continuum), and then pointing the bolome- 13 A: So, as a result of the afore-mentioned plotting, we had ter at the CO peak, and mapping around it. Sometimes two massive data-sets to play with. The SPIRE cam- I detected nothing at all. Sometimes I missed the contin- era on Herschel (of which I was by then a member of uum peak altogether, due to optical depth effects. But the consortium) was mapping huge swathes of the sky, fortunately the time allocation committee kept faith in with incredible dynamic range. It got everything from the me, and I managed to map about half a dozen of them in bright, dense, nearby regions, to the inter-stellar cirrus, the continuum. It was clear straight away that these were foreground asteroids, and back-ground high-Z galaxies – very different from Class 0 sources. They were clearly ex- all in one frame! In a sense, it became a victim of its tended, they had no jets or outflows, yet they had masses own success – how did you work out what was associated consistent with being at least virialised when compared to with your star-forming region that you were studying? In their ammonia line-widths. So I started by calling them many regions, such as our ‘control’ region around Polaris, pre-proto-stellar cores to indicate that they were at the the limitation on signal to noise was nothing to do with still earlier evolutionary stage. Eventually I realised that the instrument – it was actually the density of faint back- life was too short to be saying ‘pre-proto-stellar cores’ sev- ground high-Z galaxies! This, of course, was why SPIRE eral times a day, so I shortened it to ‘pre-stellar cores’, and was so successful, and the team that built it won an award the name stuck.