Corinne Charbonnel : Nucleosynthesis evidences of extremely massive stars in proto-globular clusters

Speaker : Dr. Corinne Charbonnel (University of Geneva) Date : 25th November 2025 Title : Nucleosynthesis evidences of extremely massive stars in proto-globular clusters-like conditions from high redshift to the local universe Abstract : The peculiar abundance patters observed in old globular clusters in the local universe as well as in very compact, intensively star-forming objects at high redshift cannot be explained by classical stellar yields and standard galactic chemical evolution. Instead, they call for the very rapid pollution of the intra-cluster medium by extremely massive stars stars (up to a few thousands solar masses), which only manage to form in proto-clusters exceeding a certain threshold of mass and compactness, releasing the hot-hydrogen burning yields whose fingerprints are observed in the long lived multiple stellar populations of massive clusters. In this talk, I will present the properties of these multiple populations and discuss the scenarios that were proposed to explain their ubiquity in massive star clusters. I will focus on the current theoretical issues and open questions on star and cluster formation in different environments over a wide range in mass, metallicity, and redshift.