Environments of massive stars and the upper mass limit

TL;DR

This paper reviews the environments of massive stars in galaxies, compares them with supernovae and gamma-ray burst locations, and discusses the potential upper mass limit of stars, including implications for supernova brightness.

Contribution

It provides a comprehensive review of massive star environments and explores the existence and implications of an upper stellar mass limit.

Findings

Massive stars are found in diverse environments from associations to dense clusters.

Comparison shows similarities between massive star locations and those of certain supernovae and gamma-ray bursts.

Very massive stars may lead to exceptionally bright supernovae, indicating an upper mass limit.

Abstract

The locations of massive stars (> 8 Msun) within their host galaxies is reviewed. These range from distributed OB associations to dense star clusters within giant HII regions. A comparison between massive stars and the environments of core-collapse supernovae and long duration Gamma Ray Bursts is made, both at low and high redshift. We also address the question of the upper stellar mass limit, since very massive stars (VMS, Minit >> 100 Msun) may produce exceptionally bright core-collapse supernovae or pair instability supernovae.