Stars of the γ Cas type (γ Cas analogs) belong to a small group of Be stars with a high X-ray luminosity of 10 31 ‑ 10 33 erg/s and an anomalously high temperature of the plasma emitting in the X-ray range of 10–20 keV or more, assuming a completely thermal X-ray emission. The results of the analysis of the optical spectra of γ Cas under the program of observations on the BTA "Line profile variability in the spectra of OBA stars and the nature of their X-ray emission" and the results of a study of the archival X-ray spectra of this star in 2010–2014 based on observations on the XMM-Newton satellite are presented. The variability of the line profiles in the optical spectra and the variability of the X-ray brightness of the γ Cas star on scales from minutes to hours are found. It is assumed that the minute scale variability is associated with high modes of non-radial pulsations of stars of this type. The periods of optical and X-ray variability turned out to be close, which allows us to hypothesize that the wind structure is modulated as a result of non-radial photospheric pulsations. The anomalously hard X-ray emission from such stars can be explained in terms of the contribution of possible non-thermal X-ray emission resulting from Compton backscattering of UV photons by relativistic electrons.
Original languageRussian
Pages (from-to)86-92
Number of pages7
JournalНаучные труды Института Астрономии РАН
Volume8
Issue number2
DOIs
StatePublished - 31 Oct 2023

    Scopus subject areas

  • Astronomy and Astrophysics

ID: 115316603