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UID:UW-Physics-Event-3364
DTSTART:20140616T203000Z
DTEND:20140616T220000Z
DTSTAMP:20260419T185933Z
LAST-MODIFIED:20140612T172140Z
LOCATION:4421 Sterling Hall
SUMMARY:THE  (NOT-SO) SIMPLE STELLAR POPULATIONS OF GLOBULAR CLUSTERS\
 , SPECIAL MONDAY TALK\, Henny Lamers\, University of Amsterdam
DESCRIPTION:Globular clusters were once thought to be simple stellar p
 opulations:with all stars having the same age and the same initial com
 position. However\, in recent year it has become clear that each clust
 er contains different populations with specific abundance patterns. Th
 e most striking ones are multiple main sequences(indicating different 
 He-abundances)\, the Na-O anti-correlation and the Mg-Al anti-correlat
 ion.This has been interpreted as a sign that each cluster had several 
 episodes of star formation\, i.e. multiple generations\, where each ne
 w generation is formed from mass ejected by evolved stars. The propose
 d polluters are: AGB stars\, rapidly rotating massive stars\,&lt\;br&g
 t\;<br><br>
\nor interacting massive binaries. This interpretation has
  several serious problems: a mass budget problem\, a gas-retention pro
 blem\, &lt\;br&gt\;<br><br>
\nan IMF problem and a Li-problem. Last ye
 ar we proposed a new model in which the observations are explained by 
 one single star forming event with the low mass stars\,polluted by eje
 cta from the massive stars of the same event(Bastian et al. 2013\, MNR
 AS 436\, 2398)This model overcomes some of the serious shortcomings of
  the multiple generation models. I will discuss this model and the res
 ults of recent studies that support it.
URL:https://www.physics.wisc.edu/events/?id=3364
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