Supernovae and their expanding blast waves during the early evolution of Galactic globular clusters

TL;DR

This paper explores how supernova blast waves in early Galactic globular clusters either disperse their energy or retain metals, influencing the chemical evolution and star formation in clusters of different masses.

Contribution

It demonstrates that supernova blast waves undergo blowout in steep density gradients, explaining why only massive clusters retain supernova ejecta and become chemically enriched.

Findings

Supernova blast waves undergo blowout in steep density gradients.

Only massive clusters ($M \,\ge 10^6 M_{\odot}$) retain supernova ejecta.

Less massive clusters are not contaminated by supernovae.

Abstract

Our arguments deal with the early evolution of Galactic globular clusters and show why only a few of the supernovae products were retained within globular clusters and only in the most massive cases ($M \ge 10^6$ Msol), while less massive clusters were not contaminated at all by supernovae. Here we show that supernova blast waves evolving in a steep density gradient undergo blowout and end up discharging their energy and metals into the medium surrounding the clusters. This inhibits the dispersal and the contamination of the gas left over from a first stellar generation. Only the ejecta from well centered supernovae, that evolve into a high density medium available for a second stellar generation in the most massive clusters would be retained. These are likely to mix their products with the remaining gas, leading in these cases eventually to an Fe contaminated second stellar generation.