During the past decade astronomers have recognized that other stars with surface conditions similar to that of the sun go through "activity cycles" much like the solar sunspot cycle. It is hoped that studying stellar activity cycles will contribute to a better understanding of the sun and its effect on terrestrial conditions. The Principal Investigators propose to continue with their current NSF funded spectroscopic study of stellar activity in late type stars. They will concentrate on such variable stars as RS CVn systems, selected pre-main sequence (T Tauri) stars, BY Draconis variable stars, and magnetic solar-like stars. High precision spectroscopy of the star Procyon, with the aim of detecting p-mode oscillations, will be carried out as well. They also will be monitoring the sun as if it were a distant active star, in order to be better able to interpret stellar activity cycles. The long-term goals of this investigation are 1. to understand better the similarities and differences among active stars, 2. to determine the time scales of changes in stellar activity, and 3. to estimate the physical conditions giving rise to stellar surface activity.
