Origin of Star-to-Star Abundance Inhomogeneities in Star Clusters

TL;DR

This paper investigates how thermal instabilities in mass reinserted by young stars in clusters lead to star-to-star abundance variations, explaining the origin of multiple stellar populations in clusters.

Contribution

It introduces a bimodal hydrodynamic model of mass reinserted in clusters, linking thermal instability to chemical inhomogeneities and multiple stellar populations.

Findings

Thermal instability causes inhomogeneous chemical distributions in clusters.

Low-mass clusters tend to be chemically homogeneous, high-mass clusters show inhomogeneities.

Implications for the formation of galactic super-winds.

Abstract

The mass reinserted by young stars of an emerging massive compact cluster shows a bimodal hydrodynamic behaviour. In the inner part of the cluster, it is thermally unstable, while in its outer parts it forms an out-blowing wind. The chemical homogeneity/inhomogeneity of low/high mass clusters demonstrates the relevance of this solution to the presence of single/multiple stellar populations. We show the consequences that the thermal instability of the reinserted mass has to the galactic super-winds.