A Differential Study of Nucleosynthesis in Open Star Clusters

Abstract

Measuring the chemical composition of stars in open clusters provides the best information on the origin and evolution of these stars and clusters. When we compare compositions of the main sequence stars with those of the evolved (giant) stars in the same cluster, we can measure the results of hundreds of millions of years of fusion processes in the cores of these stars. This work presents an extensive elemental catalog of 24 individual elements, 7 in multiple ionization states, measured from high-resolution spectra (R > 40, 000) of 230 stars in 8 open star clusters. We perform a differential analysis between the main sequence and giant stars to measure elemental evolution from core nucleosynthesis. Using the main sequence turn off age of each cluster, we also analyze the temporal/mass effects on the elemental evolution. We also present rudimentary artificial intelligence and machine learning techniques used to analyze the spectra, determine cluster membership, and derive stellar atmospheric parameters and elemental abundances