NOAO > Observing Info > Approved Programs > 2004B-0210
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NOAO > Observing Info > Approved Programs > 2004B-0210 |
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PI: Sebastien Lepine, American Museum of Natural History, lepine@amnh.org
Address: Department of Astrophysics, CPW at 79th street, New York, NY 10024, USA
CoI: Michael M. Shara, American Museum of Natural History
CoI: R. Michael Rich, U.C.L.A.
Title: A search for nearby, very low-mass, ultra-cool halo subdwarfs
Abstract:
The Galactic halo is expected to host 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 vicinity of the Sun:
only a dozen subdwarfs with spectral type sdM6.0/esdM6.0 or later are
currently known. As a result, the physical properties and local
distribution 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 several hundred new candidate ultra-cool subdwarfs, some of
which have been spectroscopically confirmed in a previous KPNO observing
run. We propose to obtain spectra for all our candidates stars in order
to confirm their subdwarf status and build a complete, well-populated
spectroscopic sequence of subdwarf stars down to the hydrogen-burning
limit. Using our confirmed objects and their radial velocities, we will
also determine the local density of ultra-cool subdwarfs and constrain
their density and distribution in the Galactic halo.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2004B-0210 |
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