Stellar contents of the open clusters Be 64 and Be 69

Abstract

We present U BV RI CCD photometry for previously unstudied open clusters (Be 64 and Be 69). Photometry has also been carried out for nearby fields to correct for the effects of field stars contamination. From the colour-colour diagram the reddening for Be 64 and Be 69 is estimated to be ∼ 1.05 mag and ∼ 0.65 mag respectively. In case of Be 69 the comparison of observational colour - magnitude diagram (CMD) with the standard isochrones of VandenBerg (1985) indicates an apparent discrepancy between the shape of the turnoff and isochrones. The morphological features of the CMDs of Be 69 are better understood in terms of convective overshooting. The comparison of CMDs of both the clusters with the convective overshoot models (Bertelli et al. 1994) produces a good fit for a metallicity Z = 0.008 and age = 0.8 - 1.0 Gyr. An apparent distance modulus (m - M) = 16.2 and 14.3 has been estimated for Be 64 and Be 69, respectively, which corresponds to a distance of 3880 ± 480 pc and 2860 ± 310 pc, respectively.