Sneh Lata*, V. Mohan and R. Sagar
Aryabhatta Research Institute of Observational Sciences,
Manora Peak, Naini Tal 263 129, Uttaranchal
Abstract. We present UBV RI CCD photometry of three open star clusters Be 15, Be 71 and King 1 for the fist 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.
Keywords: open clusters: Be 15, Be 71 and King 1-colour-magnitude diagram