AAS 205th Meeting, 9-13 January 2005
Session 77 Properties of Stars
Oral, Tuesday, January 11, 2005, 10:00-11:30am, Royal Palm 4-6

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[77.02] Common Proper Motion Binaries: a Gold Mine for Galactic Studies

J. Chanamé (The Ohio State University)

We construct the largest catalog of genuine wide binaries (a > 100 AU) in the solar neighborhood available today and cleanly classify each entry as belonging to either the disk or the halo of the Galaxy. These samples are drawn from the revised New Luyten Two-Tenths (rNLTT) catalog of Salim & Gould and are complete to projected separations of 500" and 900", corresponding to about 0.1 and 1 pc, respectively. I briefly review the main steps in their selection and classification, which make use of a variety of astrometric and photometric data. I then present the most important results derived from this wide-binary catalog, with implications on issues such as star formation in the early Galaxy, the nature of halo dark matter, the age of the stellar halo, and accurate geometric distances to low-mass field stars. Finally, I outline the prospects for using SDSS in the construction of a catalog of halo wide binaries which, by greatly improving the statistics at physical separations crucial for dark matter studies, will enable direct exploration of regimes of MACHO masses that are only marginally accessible, if at all, by the decades-long microlensing campaigns, particularly in the astrophysically important regime of heavy stellar remnants.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.