Investigation of the Hα spectral line and the Na D sodium doublet in the spectrum of the post-AGB star HD 161796

Variability of the profile of the H α line and the Na D sodium doublet in the spectrum of HD 161796 was studied based on the spectrograms obtained with the 2-meter telescope of Shamakhy Astrophysical Observatory (National Academy of Sciences of Azerbaijan). It was found that the radial velocity and the equivalent width of the H α line profile and the equivalent width of the sodium doublet vary in synchrony with changes in the V light curve amplitude that occur with a known period P of 62 days. The radial velocity of the D 2 line of the sodium doublet (Na I λ 588.9953 nm) varies in antiphase with the variations of the V light curve, the radial velocity of the H α line, and the equivalent widths of H α and D 2 .