2006AJ....131.2543C

The globular cluster ESO 452-SC11 has been observed using Johnson V and Cousins I filters, and point-spread function photometry has been performed. The resulting color-magnitude diagrams were compared to theoretical isochrones to derive the cluster's age, overall chemical composition, and distance modulus. These isochrone models include those published by Girardi et al. and Bergbusch & VandenBerg, with BVRI color-T_effrelations as described by VandenBerg & Clem, and Demarque et al. (known as the Yale isochrones). From the Yale isochrones, it is estimated that the cluster has an age of 9-11 Gyr, a metallicity -1.4 dex≤[Fe/H]≤-1.0 dex, and a distance modulus (m-M)_V=16.10-16.31 mag, resulting in a heliocentric distance of 7.3-7.5 kpc. Using the Bergbusch & VandenBerg models, it is estimated that the cluster has an age of 11-13 Gyr, with an iron-to-hydrogen ratio in the range -1.3 dex≤[Fe/H]≤-0.8 dex, a distance modulus (m-M)_V=15.87-16.12 mag, and a heliocentric distance between 7.0 and 7.2 kpc. The Girardi isochrone models yield a derived age of 13-16 Gyr, metallicity -1.3 dex≤[Fe/H]≤-0.4 dex, distance modulus (m-M)_V=15.59-16.19 mag, and heliocentric distance between 6.6 and 7.1 kpc. The derived parameters from these models are consistent for -1.3 dex≤[Fe/H]≤-1.0 dex, 0.70≤E(V-I)≤0.76, and (m-M)_V=16.10-16.12 mag. The range of values provided can be used as a starting point for future investigations of both independent cluster properties and comparison of differences among theoretical isochrone models.