CCD photometry of the galactic star clusters Be 15, Be 71 and King 1

Abstract

We present U BV RI CCD photometry of three open star clusters

Be 15, Be 71 and King 1 for the first time. Base on these data, optical colour-

magnitude diagrams (CMDs) for the stars in the clusters down to V = 22 mag

are studied. There are 1408, 1887 and 2485 stars located in the regions of Be 15,

Be 71 and King 1 respectively. We also provide estimates of their fundamental

parameters such as radius, reddening, distance and age. The radius values for

the clusters Be 15, Be 71 and King 1 are 4.5, 3.0 and 4.0 arcmin respectively.

The corresponding distances are 3.0±0.3,3.9±0.4 and 1.9±0.2 kpc respectively

while the ages are log (age)=8.5±0.1, 8.8±0.1 and 9.2±0.1 respectively. The

red giant clump is clearly visible in the CMDs of cluster King 1.