Optical spectroscopy of Be stars: peak separation of Balmer emission lines
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 ($ΔV_α$, $ΔV_β$, and $ΔV_γ$ 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 $ΔV_α$, $ΔV_β$ and $ΔV_γ$. They are effective for $30 \le ΔV_α\le 500$ km s$^{-1}$, $80 \le ΔV_β\le 600$ km s$^{-1}$, and $40 \le ΔV_γ\le 300$ 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.
astro-ph.SR↗