Y. M. Maharramov


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.

Ключові слова

supergiant star; stellar atmosphere; P Cyg profile; Hα and Hβ line profiles

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