CCD Light Curves of Young, Low Mass Stars (Abstract)

Volume 21 number 1 (1992)

J. Stauffer

Harvard-Smithsonian Center for Astrophysics, Cambridge, MA

C. Prosser

Harvard-Smithsonian Center for Astrophysics, Cambridge, MA

R. Schild

Harvard-Smithsonian Center for Astrophysics, Cambridge, MA

Abstract

(Abstract only) Most young low mass stars are much more heavily spotted than the present-day Sun, and accurate monitoring of their luminosity often shows detectable photometric variability modulated with the rotation period of the star. These light curves, which are best obtained with CCD cameras on small telescopes, provide crucial information on the formation and early evolution of stars like the Sun. From CCD photometry, we have obtained new light curves and periods for at least 8 stars in the Pleiades and for alpha Per. Photometric (and hence rotational) periods observed range form 0.2 to 1.5 days and amplitudes from 0.03 to 0.2 magnitude. The stars observed have average V magnitudes in the range form V = 12 to around V = 15.5. We have also obtained new light curves for some stars for which periods had previously been determined For one Pleiades member (HII 1883, period = 0.25 day), light curves spanning nearly a decade show possible evidence for a sunspot cycle in this, the most rapidly rotating low mass star known in the Pleiades. We discuss the uses of these light curves in understanding the rotational velocity evolution of low mass stars. We hope eventually to obtain rotation periods for about 100 low mass stars in the forming regional. We have assembled a small team to work on this program, but would be glad to enlist others who have ready access to small telescopes with CCD cameras.