ROSAT pointed observations of the Alpha Persei cluster

We extend the results of a previous ROSAT x-ray raster survey of the open cluster alpha Persli by the analysis of three 22-25 ksec ROSATPSPC pointings in this relatively nearby (d similar to 170 pc) and young (age similar to 50 Myr) open cluster. The present study reports on those catalogued stars in the cluster region which are found to be associated, or possibly associated, with an x-ray sourer. Out of a total of 222 sources, approximately 80 sources are identified with a catalogued star, We detect all previously known K dwarfs, and a majority of M dwarfs within the higher sensitivity, inner PSPC regions. The results from the deep pointings are consistent with those from the previous raster survey of this cluster in terms of the x-ray luminosities measured for sources in common, the detection frequencies among cluster members as a function of spectral type, and the distribution of L(X) as a function of color. The x-ray detections and upper limits provided by the PSPC observations have been combined with the raster survey results to create a merged raster/PSPC dataset reflecting the x-ray properties of the alpha Per cluster. The upsilon sin i-activity relation among G/K members is reviewed using the combined dataset. The alpha Per members with upsilon sin i > 30 km/s all show saturated levels of coronal activity, with the saturation level decreasing slowly from log(L(X)/L(bol))similar to-3 at 50 km/s to log(L(X)/L(bol)similar to-3.4 at 200 km/s. The stars with upsilon sin i < 15 km/s, most with only upsilon sin i upper limits, show a wide range in coronal activity (-4.3 < L(X)/L(bol) < -2.9), we assume that coronal activity in alpha Per increases with increasing rotation rate for v sin i < 15 km/s, but the functional form of the relation cannot be determined from existing data. The x-ray luminosity distribution functions among F-M alpha Per stars have been recomputed using the merged raster/PSPC dataset and compared to the Pleiades. The findings of the raster survey are confirmed, with F and G alpha Per dwarfs clearly exhibiting higher average emission than their Pleiades counterparts, while alpha Per K dwarfs show only slightly higher activity. The revised alpha Per M dwarf XLDF is in closer agreement with the Pleiades M dwarf distribution. We discuss the apparent detection in x rays of the one evolving blue supergiant member or this cluster, a Per itself. In addition, the sensitive PSPC observations may have detected x-ray sources associated with very low mass candidate cluster members al spectral type similar to M5. We also provide a summary of the x-ray flare characteristics (peak similar to 10(31) ergs/s) for three alpha Per members. (C) 1996 American Astronomical Society.