BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//ZContent.net//ZapCalLib 1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20110707T000000
DTEND;TZID=Atlantic/Canary:20110707T010000
UID:iactalks-268
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/268
CREATED:2011-07-07T00:00:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:The Formation of Molecular Clouds and Massive Stars
DESCRIPTION:The Formation of Molecular Clouds and Massive Stars\nProf. Mord
 ecai-Mark Mac Low\n\nIn this talk I consider two questions. First, I inves
 tigate the formation of molecular clouds from diffuse interstellar gas. It
  has been argued that the midplane pressure controls the fraction of molec
 ular hydrogen present, and thus the star formation rate. Alternatively, I 
 and others have suggested that the gravitational instability of the disk c
 ontrols both. I present numerical results demonstrating that the observed 
 correlations between midplane pressure, molecular hydrogen fraction, and s
 tar formation rate can be explained within the gravitational instability p
 icture. Second, I discuss how ionization affects the formation of massive 
 stars. Although most distinctive observables of massive stars can be trace
 d back to their ionizing radiation, it does not appear to have a strong ef
 fect on their actual formation. Rather, I present simulations suggesting t
 hat stars only ionize large volumes after their accretion has already been
  throttled by gravitational fragmentation in the accretion flow. At the sa
 me time these models can explain many aspects of the observations of ultra
 compact H II regions.
END:VEVENT
END:VCALENDAR