NOAO >   Observing Info >   Approved Programs >   2003B-0241

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Proposal Information for 2003B-0241


PI: Sebastien Lepine, American Museum of Natural History, lepine@amnh.org
Address: Department of Astrophysics, Central Park West at 79th street, New York, NY 07601, USA

CoI: Michael M. Shara, American Museum of Natural History
CoI: R. Michael Rich, UCLA

Title: A search for ultra-cool sdM and sdL subdwarfs

Abstract: Our Galaxy is expected to be host to a vast population of very low mass, metal poor stars, remnants of the first ages of star formation. While these "ultra-cool subdwarfs" should exist in large numbers, very few of them have actually been identified in the neighborhood of the Sun: only 8 subdwarfs with spectral type sdM6.0 or later are known. And as a result, the physical properties of metal-poor stars at the bottom of the main sequence are very poorly constrained. As a by-product of our all-sky survey for faint stars with large proper motions, we have recently succeeded in identifying ~100 new candidate ultra-cool subdwarfs. We propose to obtain spectra for all those stars in order to confirm their subdwarf status, and to try and build a complete spectroscopic sequence of subdwarf stars down to the hydrogen-burning limit, filling the gaps in our knowledge of the oldest stars in our Galaxy.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2003B-0241

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