Photospheric variability of the late B supergiant HD 199478

Abstract

ABSTRACT We present the results of spectral studies of the photospheric lines of the late B supergiant HD 199478 (B8 Iae) in the visual range. The radial velocities of photospheric lines, as well as the emission component of the Hα line, demonstrate synchronous variations. The variations in the equivalent widths of the photospheric lines and the emission component of the Нα line tend to be anticorrelated. The parameters of the spectral lines vary quasi-periodically and are characterized by extrema. The time-scales between the nearby extrema are about 25 d, and the full cycle of the quasi-period is about 45 ± 10 d. The D Na i line profiles often exhibit signs of accretion of matter on to the star. It is shown that the observed photometric variability of the star can also be explained by radial pulsations.