TY - JOUR

T1 - Analysis of X-Ray Emission from OB Stars

T2 - IV. About X-Ray Emission from Inhomogeneous Winds of OB Stars

AU - Рыспаева, Елизавета Борисовна

AU - Холтыгин, Александр Федорович

PY - 2023

Y1 - 2023

N2 - 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 τu ∼ 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.

AB - 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 τu ∼ 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.

KW - stars: early-type stars

KW - Stars: statistics

KW - X-rays: stars

UR - http://www.scopus.com/inward/record.url?scp=85174902450&partnerID=8YFLogxK

U2 - 10.1088/1674-4527/acf030

DO - 10.1088/1674-4527/acf030

M3 - Article

VL - 23

JO - Research in Astronomy and Astrophysics

JF - Research in Astronomy and Astrophysics

SN - 1674-4527

IS - 10

M1 - 105016

ER -