Study of the non-stationarity of the atmosphere of κ Cas. Ii. Variability of the Hγ, Hβ, and Hα wind-line profiles

Abstract

We study the variability of the Hγ, Hβ, and Hα line profiles in the spectrum of the supergiant κ Cas. The variability pattern proved to be the same for all the lines considered: their profiles are superimposed by blueshifted, central, and redshifted emission. For Hγ the positions of the emissions coincide with the positions of the corresponding emissions for He I λλ 5876, 6678 Å lines, and are equal to about −135 ± 30.0 km s⁻¹, −20 ± 20 kms⁻¹, and 135 ± 30.0 kms⁻¹, respectively, whereas the three emissions in the Hβ profiles are fixed at about −170.0 ± 70.0 kms⁻¹, 20 ± 30 kms⁻¹, and 170.0 ± 70.0 km s⁻¹, respectively. The positions of the blueshifted and central emissions for Hα are the same as for Hβ, with additional blueshifted emission at −135.0 ± 30.0 kms⁻¹, whereas no traces of emission can be seen in the red wing of the line. These emissions show up more conspicuously in wind lines, however, their traces can be seen in all photospheric lines. When passing from wind lines to photospheric lines the intensity of superimposed emission components decreases and the same is true for the absolute values of their positions in line wings expressed in terms of radial velocities. The V/R variations of the lines studied found in the spectrum of κ Cas and the variability of the Hα emission indicate that the star is a supergiant showing Be phenomenon.