ADDITIONAL EVOLUTIONARY STELLAR MODELS WITH CORE OVERSHOOTING AND MASS-LOSS - APSIDAL MOTION CONSTANTS

In order to extend the range of available chemical compositions and masses of our previously published grid of stellar evolutionary models used to analyse apsidal motion observations (Claret & Gimenez 1991b), we have carried out new model calculations taking into account core overshooting and mass loss. Four additional chemical compositions were in fact adopted apart from the standard solar composition (X, Z) = (0.70, 0.02). On the other hand, we have also extended the calculations for our standard model (Claret & Gimenez, 1989), as well as the non-standard one with solar composition (Claret & Gimenez 1991b), up to values of log M = 1.6. The main reason to do this is to allow a straight comparison between observational data and theoretical models of massive binaries showing apsidal motion variations and also to permit the study of the effect of adopting different initial chemical compositions. Recent opacity tables from Los Alamos (Huebner et al. 1977) as well as revised rates of nuclear burning have been used (Fowler et al., 1975; Harris et al. 1983) and the internal stellar structure constants were computed for all the models presented.