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Session 80 - Star Clusters in the Milky Way.
Display session, Friday, January 09
Abundance patterns in globular cluster stars -- such as enhanced alpha element ratios -- indicate enrichment from ejecta of Type II supernovae. These supernovae can produce widely varying element abundances depending on the masses of their progenitors. Thus, two globular clusters with the same overall metallicity could have different metal constituents, depending on the masses of the supernovae that enriched the gas from which they formed.
In low-metallicity GC's, the number of supernovae required for enrichment is small, but increases with the amount of gas that contributed to star formation in the cluster. As the number of supernovae contributing increases, so the variance in abundance ratios decreases. We thus argue that the spread in abundance ratios from cluster to cluster provides information on the amount of gas that contributed to the formation of the cluster and could, in principle, distinguish between `pre-enrichment' and `self-enrichment' scenarios of chemical enrichment.
In this work, we perform Monte Carlo simulations of the chemical enrichment of gas masses in the range 10^4M_ødot to 10^9M_ødot. We determine the variances of abundance ratios expected for systems with 3 different metallicities and discuss prospects for observing this effect in globular clusters. We also note possible applications to the study of QSO absorption line systems and to the study of halo formation.
Program listing for Friday