Corinne Charbonnel (CNRS, France & Geneva Observatory, Switzerland)

Title: Multiple stellar generations in globular clusters

Abstract: Galactic globular cluster stars exhibit abundance patterns
that are not shared by their field counterparts, namely the
well-documented O-Na, C-N, Mg-Al anticorrelations.  Recent
observations provide compelling evidence that these abundance
anomalies were already present in the intracluster gas from which the
presently observed stars formed.  The current explanation is that the
gas was polluted very early in the history of the globular cluster by
material processed through H-burning at high temperature and then lost
by stars more massive than the long-lived stars we still observe
today.  However the "polluters" have not been unambiguously identified
yet.  Most studies have focused on AGB stars, but rotating massive
stars present an interesting alternative.  In this talk I will
critically analyse the pros and cons of both potential stellar
polluters. I will discuss the constraints that the observational data
bring on stellar nucleosynthesis and hydrodynamics, as well as on the
formation and early evolution of very massive star clusters.