Dartmouth Events

Abstract: The definition of globular clusters (GCs) has changed over the past several decades from one which described these structures as single stellar populations to the current one of GCs as hosts to multiple stellar populations.  In treating GCs as single stellar populations we determine the distance, absolute ages and orbital trajectories of these structures via comparisons to theoretical stellar evolution models, the results of which ultimately informing us further on the role of GCs in the formation of the Milky Way.  However, we learn even more by studying their multiple stellar populations.  High resolution spectra of three GCs (NGC6681, NGC6584 and NGC7099) are obtained for a detailed abundance analysis of red giant branch stars. The high signal-to-noise achieved in these observations allows for the discovery of statistically significant Na-O anti-correlations in these clusters, the populations of which agree with those from photometric observations. Although we cannot determine precisely the nature of the polluters that were the predecessors to the enhanced populations, we do know that, in all three clusters, both s-process and r-process mechanisms contributed to the evolution and these results can be used to help constrain future models of GC polluter candidates.