Seventy-two grids of stellar evolutionary tracks, along with the capability to generate isochrones and luminosity/color functions from them, are presented in this investigation. 1 Sixty of them extend (and encompass) the sets of models reported by VandenBerg et al. (2000, ApJ, 532, 430) for 17 [Fe/H] values from −2.31 to −0.30 and α-element abundances corresponding to [α/Fe] = 0.0, 0.3, and 0.6 (at each iron abundance) to the solar metallicity and to sufficiently high masses (up to ∼ 2.2M ⊙ ) that isochrones may be computed for ages as low as 1 Gyr. The remaining grids contain tracks for masses from 0.4 to 4.0 M ⊙ and 12 [Fe/H] values between −0.60 and +0.49 (assuming solar metal-to-hydrogen number abundance ratios): in this case, isochrones may be calculated down to ∼ 0.2 Gyr. The extent of convective core overshooting has been modelled using a parameterized version of the Roxburgh (1989, A&A, 211, 361) criterion, in which the 1 All of the model grids may be obtained from the Canadian Astronomy Data Center (http://www.cadc-ccda.hiaiha.nrc-cnrc.gc.ca/cvo/community/VictoriaReginaModels/). Included in this archive are (i) the interpolation software (FORTRAN 77) to produce isochrones, isochrone probability functions, luminosity functions, and color functions, along with instructions on how to implement and use the software, (ii) BV RI (VandenBerg & Clem 2003) and uvby (Clem et al. 2004) color-temperature relations, and (iii) Zero-Age Horizontal Branch loci for all of the chemical compositions considered.value of the free parameter at a given mass and its dependence on mass have been determined from analyses of binary star data and the observed color-magnitude diagrams for several open clusters. Because the calculations reported herein satisfy many empirical constraints, they should provide useful probes into the properties of both simple and complex stellar populations.

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An isochrone population function (IPF) gives the relative distribution of stars along an isochrone. IPFs contain the information needed to calculate both luminosity functions and color functions, and they provide a straightforward way of generating synthetic stellar populations. An improved algorithm for interpolating isochrones and IPFs, based on the scheme introduced by Bergbusch & VandenBerg, is described. Software has been developed to permit such interpolations for any age encompassed by an input grid of stellar evolutionary tracks. Our Ðrst application of this software is to the models presented in this series of papers for 17 [Fe/H] (speciÐcally, 0.0, 0.3, and 0.6). (These models do not treat gravitational settling or radiative acceleration processes, but otherwise they are based on up-to-date physics. Additional grids will be added to this database as they are completed.) The computer programs (written in FORTRAN 77) and the grids of evolutionary tracks that are presently available for processing by these codes into isochrones and IPFs are freely available to interested users. In addition, we add to the evidence presented in previous papers in this series in support of the and color scales of our models. In particular, the T eff temperatures derived by Gratton et al. for local Population II subdwarfs with accurate (Hipparcos) parallaxes are shown to be in excellent agreement with those predicted for them, when the Gratton et al.[Fe/H] scale is also assumed. Interestingly, the locus deÐned by local subdwarfs and subgiants on the and the morphologies of globular cluster (GC) color-magnitude diagrams are well (M V , log T eff )-plane matched by the present models, despite the neglect of di †usion, which suggests that some other process(es) must be at play to limit the expected e †ects of gravitational settling on predicted temperatures. The three Ðeld halo subgiants in our sample all appear to have ages Gyr, which is Z15 favored for the GalaxyÏs most metal-poor GCs as well. (The settling of helium and heavy elements in the central regions of stars is expected to cause about a 10% reduction in these age estimates : this e †ect should persist even if some process, such as turbulence at the base of the convective envelope, counteracts di †usion in the surface layers.) Furthermore, our isochrones accurately reproduce the Da Costa & Armandro † red giant branch Ðducials for M15, NGC 6752, NGC 1851, and 47 Tuc on the [M I , However, our models fail to predict the observed luminosities of the red giant bump (V [I)

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We present a statistical analysis of color-magnitude diagrams of 47 Tuc derived from original and archival BVI photometry that produces the most probable locus for single stars. After adopting E(B −V ) = 0.04, we derive an apparent distance modulus (m − M) V = 13.375 and achieve good matches to the most probable locus in the isochrones from the Victoria-Regina models. This metallicity is generally lower than recent spectroscopically derived estimates for the cluster, but it is reinforced by the main-sequence match with a sample of subdwarfs.

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