Analysis of X-Ray Emission from OB Stars. IV. About X-Ray Emission from Inhomogeneous Winds of OB Stars  

作　　者：Elizaveta Ryspaeva Alexander Kholtygin 

机构地区：[1]Crimean Astrophysical Observatory,Nauchny,Crimea,Russia [2]Saint-Petersburg State University,Saint-Petersburg,Russia

出　　处：《Research in Astronomy and Astrophysics》2023年第10期387-405,共19页天文和天体物理学研究（英文版）

基　　金：the support by the Russian Science Foundation grant 23-22-00090。

摘　　要：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)~ 10^(8)–10^(13)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.

关 键 词：stars:early-type stars:statistics X-rays:stars 

分 类 号：P172.2[天文地球—天文学]