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Douglas Geisler
Universidad de Concepción
& NOAO South Visiting Astronomer
 

"The Nine Lives of Omega Centauri"
 

Omega Centauri is a unique object in the Galaxy. It is the brightest and most massive globular cluster.  It is the first such object which clearly showed that globulars are not the Simple Stellar Populations they are generally assumed to be but at least some instead show evidence of multiple populations, with more than a single age and/or metallicity component being present. It is now generally agreed that Omega Cen is in fact the remnant of a dwarf galaxy, making it the nearest galaxy. Studying the detailed chemical evolution of such an object can help us to understand cluster and galaxy formation, the role of different types of supernovae, the nature of the polluters required to produce the properties of the multiple populations we see today, etc.

We present detailed abundances for a number of different elements for a very large sample of stars in a variety of evolutionary stages in Omega Cen, based on VLT + FLAMES multiobject spectra.  We discuss the intriguing     results, including evidence for at least 9
different metallicity populations and a multi-Gyr age spread in this fascinating object.