Colour magnitude diagrams of the moderately metal-rich globular clusters NGC 6569 and Palomar 11

Abstract

For the first time Colour-Magnitude Diagrams are presented for NGC 6569 and Palomar 11. NGC 6569 is a rather concentrated cluster whereas Palomar 11 is loose and sparsely populated. Cluster parameters are derived from V and I photometry. These are red Horizontal Branch globular clusters, with metallicities comparable to that of 47 Tucanae. We derive a reddening E(B − V ) ≈ 0.53 and a distance from the Sun dʘ ≈ 9.8 kpc for NGC 6569, and E(B − V ) ≈ 0.35 and dʘ 13.2 kpc for Palomar 11. NGC 6569 is located in the bulge, while Palomar 11, despite its rather high metallicity, is in the inner halo, a rare case similar to that of 47 Tucanae.