The Be stars display variable optical emission lines originating in the circumstellar disc. Here we analyse high resolution spectroscopic observations of Be stars and the distance between the peaks of H-alpha, H-beta, and H-gamma emission lines ($\Delta V_\alpha$, $\Delta V_\beta$, and $\Delta V_\gamma$ respectively). Combining published data, spectra from the ELODIE archive (obtained in the period 1998 -- 2003) and Rozhen spectra (obtained 2015 -- 2023) of 93 Be stars, we find a set of relations connecting $\Delta V_\alpha$, $\Delta V_\beta$ and $\Delta V_\gamma$. They are effective for $30 \le \Delta V_\alpha \le 500$ km s$^{ -1}$, $80 \le \Delta V_\beta \le 600$ km s$^{ -1}$, and $40 \le \Delta V_\gamma \le 300$ km s$^{ -1}$. The new equations are in the form $y=ax + b$ and are valid for a wider velocity range than in previous studies.
Categories: astro-ph.SR