Astron. Astrophys. Suppl. Ser. 141, 371-383

Evolutionary tracks and isochrones for low- and intermediate-mass stars: From 0.15 to 7 $M_{\odot }$, and from Z=0.0004 to 0.03

L. Girardi^1,2,3 - A. Bressan⁴ - G. Bertelli^1,5 - C. Chiosi¹

Send offprint request: L. Girardi,
e-mail: Lgirardi@pd.astro.it

1 - Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy
2 - Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85740 Garching bei München, Germany
3 - Instituto de Física, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre RS, Brazil
4 - Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy
5 - Consiglio Nazionale delle Ricerche (CNR), Italy

Received June 17; accepted October 29, 1999

Abstract:

We present a large grid of stellar evolutionary tracks, which are suitable to modelling star clusters and galaxies by means of population synthesis. The tracks are presented for the initial chemical compositions [Z=0.0004, Y=0.23], [Z=0.001, Y=0.23], [Z=0.004, Y=0.24], [Z=0.008, Y=0.25], [Z=0.019, Y=0.273] (solar composition), and [Z=0.03, Y=0.30]. They are computed with updated opacities and equation of state, and a moderate amount of convective overshoot. The range of initial masses goes from $0.15~M_{\odot}$ to $7~M_{\odot}$, and the evolutionary phases extend from the zero age main sequence (ZAMS) till either the thermally pulsing AGB regime or carbon ignition. We also present an additional set of models with solar composition, computed using the classical Schwarzschild criterion for convective boundaries. From all these tracks, we derive the theoretical isochrones in the Johnson-Cousins UBVRIJHK broad-band photometric system.

Key words: stars: evolution -- stars: interiors -- stars: Hertzsprung-Russell (HR) diagram -- stars: low-mass