Hα AND Hβ PROFILE VARIATIONS IN THE SPECTRA OF THE STAR 55 CYG

Abstract

We study the variability of the Hα and Hβ lines in the spectra of 55 Cyg based on observations acquired in 2014 on the 2-m telescope of Shamakhy Astrophysical Observatory. In this work line profiles of Hα and Hβ are described extensively and compared with early observations. The profile of Hα line vanishes or almost vanishes in the spectra on some epochs again. Our observations showed that when the Hα line disappeared or weaken sharply in the spectra, the HeI and Hβ line are redshifted, but no synchronous variabilities were observed in other spectral lines (CII and others) formed in deeper layers of the stellar atmosphere. In addition, the profiles of the Hα and Hβ lines have been analysed, as well as their relations with possible conditions of the atmosphere of 55 Cyg. We revealed that the structures of photospheric (CII, HeI etc.) absorption line profiles, as well as Hβ line, their radial velocities and equivalent widths are variable. These events may be associated with a manifestation of the non-stationarity of the atmosphere or non-sphericity of the stellar wind.