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Deep CCD photometry in the globular cluster M10 Hurley, Daniel Joseph Colman


CCD observations of the galactic globular cluster NGC 6254 (M10), obtained at the Canada-France-Hawaii 3.6m telescope, have been reduced and analysed. A color-magnitude diagram of the cluster which extends below V = 21 is presented. The basic observational parameters of distance modulus, reddening and metallicity are derived. The latter two values are in excellent agreement with results in the literature. The distance modulus is 0m3 larger than previous estimates. Possible implications of this discrepancy are considered. The morphology of the color-magnitude diagram, in particular the very blue horizontal branch which is observed down to the turnoff luminosity, is discussed in terms of the "second parameter" problem. The age of M10 is estimated to be 17 ± 1 Gyr, through use of Vandenberg and Bell's (1985) isochrones. A comparison to the color-magnitude diagram of NGC 288 produced by Bolte (1989b) to that of M10 indicates that these two clusters are coeval. Luminosity functions are generated for the three fields observed in M10 and translated into mass functions. By comparing those mass functions to multimass King models a global mass function exponent of x[sub global] = 0-5 ± 0.5 is found. The mass function is quite uniform in slope in the range 0.5-0.8M©. NO firm evidence for mass segregation was seen, but these data are not particularly sensitive to such effects.

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