1996A&A...309..530Z

A total of 18 high S/N Hα spectra were obtained of the chromospherically active binary HR 1099 (V711 Tau) within more than two consequent orbital cycles in 1993 season. By using the multiple Gaussian fitting technique, it was found that the equivalent width of the Hα excess emission above the continuum of the K1IV component had an average level of EW=0.988A and basically no phase-modulated variations, though the peak intensity as well as the half width of it were phase-dependent. An abrupt increase by 27% in Hα excess emission of the K1IV component was detected near the third orbital cycle which may be caused by some short-lived but large-scale event. There were definitive weak Hα absorption on the trailing hemisphere but no detectable Hα line feature on the leading side to be observed for the G5IV component. Together with the other additional emissions or absorptions with high velocity shifts, a mass transfer model is postulated which can essentially account for the observed Hα line structure and the variations as a whole.