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Session 55 - New Digital Sky Surveys.
Display session, Wednesday, June 10
We present a study of the very-low-mass (0.1 < M < 0.3 solar masses) metal-poor stellar population of the Galactic halo based upon a new sample of proper-motion stars discovered using the Palomar Sky Surveys. We find that the metallicity distribution of these stars is consistent with that of halo G stars. The kinematics of the VLM stars is also consistent with that determined locally for higher mass metal-poor stars. Transformation of our observed luminosity functions into the mass functions is complicated by the uncertainties in stellar models. Our best estimate is that the stellar IMF is at most weakly dependent on metallicity. In addition, we present preliminary results of a Hubble Space Telescope search for nearby binary M subdwarfs. Constraints on the binary fraction of metal-poor stars and the prospects for determining the first empirical masses for these stars are discussed.
Program listing for Wednesday