Stellar Rubella: Starspots on F, G and K Stars of Different Ages
and Rotation Periods  Previous abstract Next abstract   [21.01]
Stellar Rubella: Starspots on F, G and K Stars of Different Ages
and Rotation Periods  E.F. Guinan, L.E. DeWarf, S. Messina, and
G.P. McCook ( Villanova University)  We present high precision
photoelectric photometry of a sample of bright, single F, G, and
K- type main-sequence and subgiant stars. Several of the stars
are members of clusters or moving groups and thus have well
determined ages. The majority of the stars are main-sequence to
subgiant G-types stars that range in age from 70 Myr to 10 Gyr
with directly measured rotation periods from 2.7 days up to
40-50 days. The observations have been carried out with
Automatic Photometric Telescopes (APTs) located on Mt Hopkins,
Arizona beginning in 1988; standard UBVRI \ or uvby \ filters
were used. As expected, the youngest, fastest rotating stars in
the sample typically have the largest, rotationally modulated
starspot light variat