The evolution of massive and very massive stars in clusters

TL;DR

This paper reviews the evolution of massive and very massive stars, focusing on uncertainties in stellar wind mass loss, the role of rotation and binarity, and the nature of ultra luminous X-ray sources.

Contribution

It provides a comprehensive overview of key factors affecting massive star evolution and their implications for understanding cosmic phenomena.

Findings

Uncertainty in stellar wind mass loss rates remains significant.

Stellar rotation may be crucial for understanding massive star evolution.

Binarity is more common among massive stars than often assumed.

Abstract

The present paper reviews massive star (initial mass smaller than 120 M0) and very massive star (initial mass larger than 120 M0) evolution. I will focus on evolutionary facts and questions that may critically affect predictions of population and spectral synthesis of starburst regions. We discuss the ever-lasting factor 2 or more uncertainty in the stellar wind mass loss rates. We may ask ourselves if stellar rotation is one of the keys to understand the universe, why so many massive stars are binary components and why binaries are ignored or are considered as the poor cousins by some people? And finally, do ultra luminous X-ray sources harbor an intermediate mass black hole with a mass of the order of 1000 M0?