THE STELLAR POPULATION OF THE LUPUS CLOUDS

We present photometric and spectroscopic observations of the H alpha e mission stars in the Lupus dark cloud complex. We estimate the effecti ve temperatures of the stars from their spectral types and calculate t he reddening towards each object from the (R-I) colors. From these dat a, we derive mass and age distributions for the Lupus stars using a ne w set of pre-main sequence evolutionary tracks. We compare the results for the Lupus stars with those for a similar population of young stel lar objects in Taurus-Auriga and Chamaeleon and with the initial mass function for field stars in the solar neighborhood. From the H-R diagr ams, Lupus appears to contain older stars than Taurus. The Lupus dark clouds form a greater proportion of low mass stars than the Taurus com plex. Also, the proportion of low mass stars in Lupus is higher than t hat predicted by the Miller-Scale initial mass function, and the lowes t mass stars in Lupus are less active than similar T Tauri stars in ot her regions.