Evolutionary tracks and isochrones for low- and intermediate-mass stars:: From 0.1.5 to 7 M⊙ and from Z=0.0004 to 0.03

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-. to 7 M-. and the evolutionary phases extend ii om 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.