Cyclic variability of the circumstellar disk of the Be star<i>ζ</i> Tauri
Cyclic variability of the circumstellar disk of the Be star<i>ζ</i> Tauri
<i>Context. <i/>Emission lines formed in decretion disks of Be stars often undergo long-term cyclic variations, especially in the violet-to-red () ratio of their primary components. The underlying structural and dynamical variations of the disks are only partly understood. From observations of the bright Be-shell star <i>ζ<i/> Tau, the possibly broadest …