Distances of Globular Clusters based on Hipparcos Parallaxes of Nearby Subdwarfs

Abstract

In the present study we have determined the distance moduli for seven globular clusters M2, M3, M10, M12, NGC 2808, NGC 6229 and NGC 6752, whose metallicities are in the range -1.54 < [Fe/H] < -1.10. We have derived distances for them by the main-sequence fitting method using a sample of local subdwarfs, whose accurate parallaxes are taken from the Hipparcos Catalog. The derived distance moduli are 15.52 for M2, 14.98 for M3, 14.23 for M10, 14.03 for M12, 15.56 for NGC 2808, 17.34 for NGC 6229, and 13.29 for NGC 6752.