Modeling Variability in f/i Line Ratios for X-rays from Stellar Winds
Abstract
Massive stars are sources of X-ray emission with a variety of causes. X-rays can be produced in the colliding winds of massive binaries, or in relation to interaction between a star's wind and magnetosphere. In the case of single stars, X-rays naturally arise from embedded wind shocks owing to the line-driven wind instability. An important X-ray diagnostic is the f/i line ratio from the forbidden and intercombination line fluxes of He-like ions. The ratio is influenced by the UV radiation field of the star, and can serve as a diagnostic for the location of X-ray production in the wind. Hole & Ignace (2012) explored temporal variations that could arise in f/i ratios from stellar pulsations that modify the UV radiation. Here we explore drivers of time variability arising in the wind itself. Illustrative results are presented for the case of variable mass loss, and ramifications of the model for interpreting observations are discussed. The authors gratefully acknowledge funding support for this research with a grant from NASA (GO8-19011F; PI W. Waldron).
- Publication:
-
American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23336502D