Joint Astrophysics Colloquium
Joint Astrophysics Seminar
Promiscuity, Violence, SNIa and Planets in Star Clusters
Mike Shara
Curator and Director of the Astrophysics Group
American
Museum of Natural History, NY
Highly realistic numerical simulations of the evolution of star clusters have
become feasible in the past two years, with observations and theory now able
to directly confront each other. HST observations easily resolve stars into
the cores of the densest globular clusters, while our specialized Teraflop
computers enable computations that were a fantasy as recently as 1999. I'll
describe the HST observations of globular cluster Blue Stragglers and
`missing' planets, and compare these with the star-by-star dynamical
and stellar evolution of 30,000 and 100,000 star clusters over
1010 years. The powerful feedback between single and binary star
evolution and stellar dynamics naturally produces rich populations of
collided and merged stars (`theoretical blue stragglers') and
predicts enhanced SNIa production by orders of magnitude. Planetary systems
in dense star clusters have been followed for a Gyr, and the results aren't
pretty: bullying, rejection, cannibalism, infanticide and loneliness are
rampant. The strange orbits of many known exoplanets emerge as natural
consequences of these simulations.
Thursday, April 17th 2003, 12:30
D-423, Département de Physique, Université de
Montréal
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