Identification of new low-mass members of the Alpha Persei open cluster by ROSAT. II.

The present investigation examines possible optical counterparts to 130 X-ray sources in the region of the alpha Persei open cluster (d ~ 170pc, age ~ 50 Myr) resulting from the analysis of three 22-25 ksec ROSAT PSPC pointings. In the same manner as for 73 X-ray sources from a raster survey in alpha Per (Prosser & Randich 1998), CCD photometry is employed to obtain magnitudes and colors for stars/objects close to the X-ray positions, with additional echelle and low-dispersion Hα spectra provided for some stars. For almost 60 X-ray sources, an optical counterpart with photometry acceptable for cluster membership is identified, some of which can be excluded from membership on the basis of discrepant radial velocity or X-ray characteristics. On the order of 30 new members or likely members associated with X-ray sources have been identified based on available data. A photometric rotation period has been obtained for one rapid rotator identified in X-rays.