Influence of X-ray radiation on the hot star wind ionization state and on the radiative force

TL;DR

This paper reviews how X-ray radiation from hot stars and their winds affects the ionization state and radiative driving force, emphasizing recent modeling advances for single and binary systems with strong X-ray emission.

Contribution

It provides a comprehensive review of recent progress in modeling the impact of X-ray emission on wind ionization and radiative force in hot stars and binaries.

Findings

X-ray emission significantly alters wind ionization states.

X-ray absorption influences wind acceleration mechanisms.

Models show improved agreement with observed X-ray and wind properties.

Abstract

Hot stars emit large amounts of X-rays, which are assumed to originate in the supersonic stellar wind. Part of the emitted X-rays is subsequently absorbed in the wind and influences its ionization state. Because hot star winds are driven radiatively, the modified ionization equilibrium affects the radiative force. We review the recent progress in modelling the influence of X-rays on the radiative equilibrium and on the radiative force. We focus particularly on single stars with X-rays produced in wind shocks and on binaries with massive components, which belong to the most luminous objects in X-rays.