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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20190212T123000
DTEND;TZID=Atlantic/Canary:20190212T133000
UID:iactalks-1231
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/1231
CREATED:2019-02-12T12:30:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:A lifetime of studies in star formation
DESCRIPTION:A lifetime of studies in star formation\nDr. Hans Zinnecker\n\n
  \nIn this talk, I will review some highlights of my\nstudies of star
  formation in the past 35 years.\n\nI started my PhD thesis on the theory 
 of the stellar IMF\nin 1977 at MPE in Garching and completed it in 1981.\n
 I studied two different models: (a) hierarchical\ncloud fragmentation (sta
 r formation as a random\nmultiplicative process) and (b) competitive accre
 tion\nin a protostellar cluster. The first model predicted a\nlog-normal s
 tellar mass distribution (down to substellar\nmasses) while the second mod
 el produced a power law\n(with a slope x = -1, close to the Salpeter slope
 ). \nI will outline both models and discuss how they stood 
 \nthe test of time. \nLater, as a postdoc at ROE in Scotland (1983-87
 ), I became \nan observer (mostly at UKIRT) and turned to near-infrar
 ed \n(J,H,K) observations of young embedded star clusters, 
 \nsuch as the Orion Trapezium Cluster, using infrared arrays. \nWe ob
 served near-infrared stellar luminosity functions\nand derived the corresp
 onding stellar mass spectrum,\nusing time-dependent mass-luminosity relati
 ons based\non pre-Main Sequence evolutionary tracks (without accretion).\n
 A key cluster we studied (with HST) in the near-IR was \nR136/30Dor&n
 bsp;in the LMC, and we proved the existence of a \nlow-mass pre-Main 
 Sequence population in this starburst cluster.\n \nIn the 1990s, we c
 arried out the first direct imaging studies\nof young low-mass pre-Ma
 in Sequence binary stars and also the\nmultiplicity of massive stars, usin
 g 2D speckle interferometry\nand adaptive optics observations.\nWe al
 so discovered the first molecular hydrogen (H2) jets\nfrom deeply embedded
  low-mass protostars (HH211, HH212).  \n \nFinally, time permitt
 ing, I will describe how I turned from a\nnear-infrared stellar astronomer
  to an interstellar\nfar-infrared astronomer, working with the B747SP\nair
 -borne Stratospheric Observatory for Infrared\nAstronomy (SOFIA) at NASA-A
 mes for the last 6 years.
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