2025AJ....169..198C

We present new long-term spectroscopic observations of the very active RS Canum Venaticorum (RS CVn) star V711 Tauri (V711 Tau), obtained during several observing runs from 2005 to 2021. By means of the spectral-subtraction technique, several optical chromospheric activity indicators Ca II infrared triplet, H_α, Na I D₁, D₂ doublet, He I D₃, and H_β lines, are analyzed. V711 Tau shows strong excess emission in the chromospheric activity lines, and the emission is mainly associated with the K1 IV primary component. The G5 V secondary component also shows weak emission features. There are four optical flare events during our observations, characterized by the He I D₃ line emission features and stronger emission in other activity lines, which have similar order of magnitude as the strong flares of other active RS CVn-type stars. We separate our long-term observations to twelve observing groups, and find that V711 Tau has two active longitudes around phases 0.25 and 0.75 to dominate the activity in most of time. The chromospheric activity level shows a long-term variation, indicating possible chromospheric activity cycle. Moreover, a close spatial connection between photospheric spots and chromospheric active regions in short and long timescale is found for V711 Tau.