AAS 205th Meeting, 9-13 January 2005
Session 13 Stellar Evolution
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

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[13.08] Testing Metal-Poor Stellar Evolution Models

B. Chaboyer, S.R. Bjork (Dartmouth College)

Observations of detached double-lined eclipsing binaries provide an excellent test of single star stellar evolution models. Photometric and spectroscopic observations allow one to determine the radius, luminosity and mass of the individual stars in the binary system. The mass, metallicity, colour and absolute magnitude of OGLE-GC17, a detached double-lined eclipsing binary in Omega Cen (Kaluzny et al. 2002), are compared to stellar evolution models. This low metallicity binary ([Fe/H] = -2.2) has one star near the main sequence turn-off, and the other member of the binary system is on the subgiant branch. This strongly constrains the age of the stars and provide an excellent test of stellar evolution models. Standard stellar evolution models provide a poor match to the data. A Monte Carlo simulation has been performed, whereby the input physics used in the evolutionary models are varied over their range of uncertainties. Many of these models provide a good fit to the data on OGLE-GC17 and determine the age of OGLE-GC17 to an accuracy of +/-6%.

Research supported in part by a NSF CAREER grant 0094231 to BC. BC is a Cottrell Scholar of the Research Corporation.

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