PHOTOSPHERIC VARIABILITY OF THE LATE B-SUPERGIANT HD199478

Abstract

The results of spectral studies of photospheric lines of the late B-supergiant HD 199478 (B8Iae) in the visual range are presented. It was first-ever shown that the radial velocities of photospheric lines, as well as the emission component of the Hα line, to demonstrate synchronous variations. The equivalent widths variations of the photospheric lines and the emission component of the Hα line tend to be anticorrelation. The parameters of the spectral lines vary quasi-periodically which are characterized by extrema (maxima and minima). The time scales between the nearby extrema are about 25 days, and the full cycle of the quasi-period is about 45 ± 10 days. It was first-ever revealed that the photospheric lines show blue shifts relative to the mass center of the system during the HVA (High Velocity Absorption) event.The distribution of the velocity gradient along the line shows the existence mainly radial, and to a lesser level, non-radial pulsations.The D NaI line profiles often exhibit signs of accretion of matter onto the star. It was shown that the observed photometric variability of the star can also be explained by radial pulsations.