Analysis of X-Ray Emission from OB Stars. IV. About X-Ray Emission from Inhomogeneous Winds of OB Stars
Abstract
We study the origin of X-ray emission from OB stars due to collisions of stellar winds and/or inhomogeneities in the winds. The low-resolution X-ray spectra of a big sample of OB stars were fitted by both the stationary APEC/MEKAL models and by this model with an additional PSHOCK component describing the nonstationary X-ray emission. These spectra were also described by two-temperature PSHOCK models. More than ~50% of considered spectra can be described by the above-mentioned model combinations including the PSHOCK model and the quality of the fits appears to be better for O stars. The plasma temperature of the PSHOCK component is about 1-5 keV with the ionization timescale τ u ~ 108-1013 s cm-3. The temperature of the PSHOCK component increases with the momentum and kinetic energy of the stellar wind by a power law with an index ~0.12-0.14. Such dependencies were not revealed through modeling by the stationary APEC/MEKAL models only. At the same time the X-ray luminosity of OB stars depends on momentum and kinetic energy of their winds similarly either for stationary or for nonstationary models. We conclude that many O stars and some B stars can be sources of the nonstationary X-rays formed in their inhomogeneous stellar wind.
- Publication:
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Research in Astronomy and Astrophysics
- Pub Date:
- October 2023
- DOI:
- 10.1088/1674-4527/acf030
- Bibcode:
- 2023RAA....23j5016R
- Keywords:
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- stars: early-type;
- stars: statistics;
- X-rays: stars