Astron. Astrophys. Suppl. Ser. 144, 487-499

Age-luminosity relations for low-mass metal-poor stars

A. Weiss - H. Schlattl

Send offprint request: A. Weiss;
e-mail: aweiss@mpa-garching.mpg.de

Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany

Received October 15, 1999; accepted April 12, 2000

Abstract:

We present a grid of evolutionary calculations for metal-poor low-mass stars for a variety of initial helium and metal abundances. The intention is mainly to provide a database for deriving directly stellar ages of halo and globular cluster stars for which basic stellar parameters are known, but the tracks can also be used for isochrone or luminosity function construction, since they extend to the tip of the red giant branch. Fitting formulae for age-luminosity relations are provided as well. The uncertainties of the evolutionary ages due to inherent shortcomings in the models and due to the unclear effectiveness of diffusion are discussed. A first application to field single stars is presented.

Key words: stars: evolution -- stars: interior -- stars: Population II