1999/04/28 by Alistair R. Walker · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/300947
20 pages, 7 figures, A.J. accepted
arxiv created 1999/04/28 · openalex publication_date 1999/07/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We present a deep color-magnitude diagram for the Galactic globular cluster NGC 2808 (C0911-646), reaching 3 mag below the main-sequence turnoff. A set of local photometric standards are provided, and the mean cluster reddening and metallicity are constrained using several photometric techniques. The recently discovered unusual horizontal-branch morphology is confirmed. No significant radial population gradients are identified to within the limits of the data. We investigate the redward color spread on the main sequence previously reported by Ferraro et al. in a field centered 6 3 from the cluster center and attributed to binaries. We conclude that the spread is in the most part due to a non-Gaussian distribution of photometric errors about the main-sequence ridgeline.