Observable Constraints on Galactic Chemical Evolution Using a Uniform Sample of Open Clusters

Abstract

Models of Galactic evolution are key to our understanding of not just our Galaxy but galaxies in general. Verifying observable constraints for these models is crucial. Open clusters are among the best tracers for establishing these constraints as they are reliable tracers for chemistry and age for which an accurate distance can also be determined. Previous work using open clusters however has relied on samples constructed from multiple studies, introducing significant uncertainty into any measurements made. We present methodology for targeting open cluster member stars, and establishing a probability for their membership within a cluster. Using this criteria, we establish a large, uniform sample of open clusters leveraging the APOGEE survey. This sample of 128 clusters, 71 of which we designate 'high quality'', is used to measure Galactic abundance gradients in 16 elements. Since our sample covers a wide age range, the evolution of the abundance gradients over time is also considered. We compare to previous work and a chemical evolution model, finding reasonable agreement with our results. Finally we discuss open cluster radial migration, a poorly understood topic, and find agreement with previous work that open clusters tend to migrate away from the Galactic center.