Oxygen-enhanced Models for Globular Cluster Stars. II. Isochrones and Luminosity Functions

An extensive grid of isochrones and luminosity functions (LFs) for iron abundances in the range -2.26 to -0.47, current best estimates of the helium and oxygen contents, and ages from 5-8 Gyr to 18 Gyr are presented. A novel interpolation code is used to generate the isochrones and LFs. Comparisons of the isochrones are made with the observed fiducial sequences for a few Galactic globular clusters (GCs) and with a number of the Population II subdwarf standards that have accurate parallax-based distances to demonstrate that they are consistent with these data within current uncertainties. Illustrative fits of the computed luminosity functions, which are provided for several power-law mass functions, to the observed LFs recently reported in the literature for M92, M13, and 47 Tuc are also presented and discussed. The calculations are extensively tabulated and should be particularly useful for determining the ages of the GCs, and for population synthesis analysis, given that they are predicted for the entire magnitude range of -3 to 12.