Grids of Evolutionary Models from 0.85 to 120 Solar Masses: Observational Tests and the Mass Limits

摘要

Grids of stellar evolutionary models with composition X=0.70, Z=0.02 are computed with mass loss and moderate core overshooting. Comparisons between models and cluster observations are performed for low and intermediate mass stars in order to determine the amount of core overshooting. The comparisons cover: (1) the main sequence width of intermediate and old open star clusters, (2) the blue extension of the loops described in the HR diagram during the He-burning phase, (3) the number ratio of blue to red giants in the He-phase, (4) the luminosity difference between the yellow giants and the MS turnoff, and (5) the upper mass limit for degenerate He-burning. In agreement with the results for high mass stars, the tests clearly suggest moderate overshooting from convective cores with a distance of overshooting =0.25 H sub P, rather than in favor of no or of large overshooting. The consequence of this moderate overshooting on several stellar mass limits is substantial, but not drastic. The models also suggest that the consequences of overshooting in pre-MS evolution could be important for the further evolution of solar mass stars.