Stellar Winds

TL;DR

This paper reviews the fundamental physics of stellar winds across different types of stars, emphasizing their role in stellar evolution and galactic feedback, with a focus on massive star winds and their impact.

Contribution

It provides an overview of the physical mechanisms driving stellar winds and discusses their significance in stellar evolution, highlighting the differences across the HR diagram.

Findings

Radiative forces dominate hot star winds

Molecular and dust opacities drive cool star winds

Mass-loss rates influence stellar evolution and supernova outcomes

Abstract

Stellar winds form an integral part of astronomy. The solar wind affects Earth's magnetosphere, while the winds of hot massive stars are highly relevant for galactic feedback through their mechanical wind energy. In different parts of the stellar HR diagram different forces dominate. On the hot side of the HRD radiative forces on ionised gas particles are active, while on the cool side molecular and dust opacities take over. Moreover, due to the convective envelopes, alternative physical ingredients may start to dominate. I will describe the basic equation of motion and give a few examples, mostly focusing on the winds from massive stars. Here mass-loss rates significantly affect the stellar evolution all the way to core collapse as a supernova and/or black hole formation event.