Abstract

RUELAS-MAYORGA, A.  and  SANCHEZ, L. J.. CCD photometry of M92. Rev. mex. astron. astrofis [online]. 2005, vol.41, n.2, pp.507-522. ISSN 0185-1101.

We present Johnson B and V photometry for the galactic globular cluster M92 (NGC 6341). Photometric results for a total of ~ 30,000 stars are obtained and are plotted on a V versus (B - V) diagram. We fit theoretical isochrones to this diagram in order to get an estimate for the age of M92. The age which we find is ~ 16 x 10⁹ years with the following values for the metallicity and He-abundance: [Fe/H] = -2.03, Y = 0.235. The distance modulus to this cluster turns out to be m - M = 14.6 in accordance with that obtained by Stetson & Harris (1988). We also perform stellar counts in order to produce a luminosity function which is  successfully fitted by the same theoretical models fitted to the colour-magnitude diagram.

Keywords : Galaxy [Halo]; Globular clusters [Individual (NGC 6341)]; Techniques [Photometric].