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) about 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 about 8 x 10 exp 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) about 9 or 10.