Physics of mass loss in massive stars

TL;DR

This paper reviews various mass-loss mechanisms in massive stars across different evolutionary stages, highlighting recent insights into wind physics, extreme mass-loss events, and the influence of rotation and magnetic fields.

Contribution

It provides a comprehensive overview of mass-loss processes in massive stars, integrating recent theoretical developments and observational findings.

Findings

Line-driven winds are well-understood in O-stars and BA-supergiants.

Continuum-driven mass loss may explain LBV outbursts.

Rotation and magnetic fields significantly influence stellar wind behavior.

Abstract

We review potential mass-loss mechanisms in the various evolutionary stages of massive stars, from the well-known line-driven winds of O-stars and BA-supergiants to the less-understood winds from Red Supergiants. We discuss optically thick winds from Wolf-Rayet stars and Very Massive Stars, and the hypothesis of porosity-moderated, continuum-driven mass loss from stars formally exceeding the Eddington limit, which might explain the giant outbursts from Luminous Blue Variables. We finish this review with a glance on the impact of rapid rotation, magnetic fields and small-scale inhomogeneities in line-driven winds.