Radial Velocity Variations of the Na I D Lines for the High-Latitude Supergiant Star 89 Her

Abstract

The variations in the spectral parameters of the sodium doublet Na I D line of the high-latitude supergiant 89 Her were investigated on the basis of the spectrograms obtained at the 2-m telescope of Shamakhy Astrophysical Observatory for 1975–2017. The research has shown that, in addition to shorter periodic changes, which were found earlier by various authors, there are also long-period changes in the atmosphere of this star. It has been found that the sodium doublet Na I D line’s radial velocity of the absorption component varies with a period of 5000 days. The orbital elements of the binary system were determined for the first time within the spectral-binary system model.