Rotational modulation of chromospheric emission in cool giants and "hybrid" stars.
Stencel, R. E.; Mullan, D. J.; Brosius, J. W.
United States
Abstract
Archival data from the International Ultraviolet Explorer have been used to study temporal variations of the Mg II h and k emission lines in eight late-type giants. Evidence is presented that the variations are periodic in nature. It is argued that the periodicities can be interpreted in terms of rotation. It is found that the four fastest rotators in the sample are 'hybrid' stars.