Optical and X-ray Variability of \(\gamma\) Cas Stars: HD 45995

Abstract

The paper is devoted to the analysis of the variability of the \(\gamma\) Cas-type star HD 45995 in both optical and X-ray ranges. The variability of the line profiles of HD 45995 has been detected both for long (350–380 days) and short (11–87 minutes) time ranges. Based on the photometric light curves of HD 45995 obtained with the TESS satellite, we refined the rotation period of the star at \(P=0.8443\pm 0.0009\) days. These light curves reveal components with periods of about 11\({{}^{\textrm{h}}}\) typical for non-radial pulsations of B stars and components with periods of about 4–14 days, the nature of which is still unknown. We must note, that the latter components may be of an instrumental character, for example, due to the satellite drift. The pattern of the photometric variability, according to the TESS data, changes significantly for different observation epochs in 2018/2019 and 2020/2021. In the X-ray light curves of HD 45995, the presence of superfast variations with a period of \(P=48.5\pm 0.5\)seconds is suspected.