MEMBERSHIP OF LOW-MASS STARS IN THE OPEN CLUSTER ALPHA-PERSEI

The results of a combined astrometric, photometric, and spectroscopic search for low-mass members in the intermediate-age open cluster alpha-Persei are presented. Over 130 low-mass new members have been identified to M(V) congruent-to 12.5, almost doubling the previous number of known members. The new membership information suggests a slight upward revision of alpha-Per's age to is similar to 8 X 10(7) yr. Alpha-Per is noticeably spatially elongated in a direction parallel to the Galactic plane, most likely due to tidal deformation. Analysis of the distribution of relative H-alpha-emission strengths among alpha-Per members confirms the view that the mean H-alpha-strength decreases in increasingly older systems. Allowing for survey incompleteness, one cannot reject the idea that the luminosity function is consistent with the field luminosity function to M(V) congruent-to 9 or 10.