A 12 YEAR PHOTOMETRIC-STUDY OF LOWER MAIN-SEQUENCE HYADES STARS

Between late 1980 and early 1992, we obtained differential Stomgren b and y photometric observations of 13 Hyades stars, spectral types F5 V to K4 V. The observations achieved and sustained millimagnitude preci sion. All 10 G- and K-type stars in our sample varied on timescales ra nging from days to years. These 10 stars tended to show stronger night -to-night variation, and they also tended to be redder, during seasons when they were fainter. Rotational modulation proved to be a prominen t component of the night-to-night variation.