Properties of Low Mass Stars and Brown Dwarfs: Single vs. Close Binary Environments

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AST 0205875PI HawleySloan Digital Sky Survey (SDSS) has demonstrated that it is an unsurpassed resource for finding low mass stars, brown dwarfs and close binaries such as cataclysmic variables. This project will use the ongoing SDSS photometric and spectroscopic data during the next 3 years to amass a large database on low mass stars, both single and in close binaries. Additional follow-up data will be obtained. Undergraduate and graduate students will participate in the observations and analysis of the data. An on-line database will be made available for scientists, the public, and outreach activities. Measurements of the magnitudes, colors, spectral types, magnetic activity levels, rotation rates and ages of the late type stars will be used to infer basic physical properties (temperature, luminosity, mass and strength of the magnetic dynamo), which then will be compared for objects at different evolutionary stages in both single and close binary environments to assess the dependence of magnetic activity on rotation rate, to discover and characterize close interacting binary systems with lower mass secondaries than have previously been found, study the influence of irradiation on the low mass secondaries in close binaries, to determine if this strongly affects the outbursts in cataclysmic variables, and to determine the space density and luminosity function of low mass single stars compared with their counterparts in binary systems. ***