CCD photometry of the globular cluster Palomar 13^*

Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tsarigradsko chaussèe, BG – 1784 Sofia, Bulgaria

Send offprint request to: J. Borissova

Received: 5 February 1996
Accepted: 21 May 1996

Abstract

A new CCD photometry of the halo cluster Palomar 13 is used to construct a color - magnitude diagram in the Thuan-Gunn and the B, V photometric systems. The color-magnitude diagram of the cluster shows as already noted by Ortolani et al. (1985) an extremely poor red horizontal branch and a very sparsely populated giant branch. Seven BSS candidates are identified in the field of Palomar 13. The age of the cluster determined by fitting with the isochrones of Proffitt & Vanden Berg (1991) and Bergbusch & Vanden Berg (1992) and by a differential comparison of the color-magnitude diagram with that of Pal 5 is Gyr.