Supernova Self-Enrichment in Globular Clusters

Dr. Jeremy Bailin (University of Alabama)

Globular star clusters (GCs) used to be thought of as simple stellar populations, whose stars all formed at the same time from the same material. However, observations over the past 20 years have revealed ubiquitous chemical complexity within GCs, both in terms of their abundances of intermediate-mass elements (e.g. Na, O) and sometimes even of iron. I propose a model where the star forming clouds in which GCs form fragment in the same way as observed star forming regions in the Milky Way today, allowing core collapse supernovae from earlier-collapsing fragments to enrich stars formed in later fragments. This model provides a good match to the observed star-to-star variations of iron abundances within GCs, and provides a new window for using GC systems as clues to the formation histories of galaxies.