UBVRI CCD photometry of the two Southern galactic star clusters Berkeley 79 and Trumpler 11

Abstract

CCD observations in U, B, V, R and I passbands have been made down to V = 18.5 mag for the southern galactic star clusters Berkeley 79 and Trumpler 11. The sample consists of 60 and 358 stars respectively. Berkeley 79 seems to have non-uniform extinction over the observed region with a median value of E(B - V) = 1.19 (±0.05) mag while a uniform reddening with E(B - V) = 0.21 (±O.02) mag appears to be present over the face of Trumpler 11. The distances to the clusters Berkeley 79 and Trumpler 11 have been estimated as 2.3 ± 0.2 kpc and 3.1 ± 0.3 kpc respectively. Based on the isochrones fitting to the bright stars, an age of ~65 Myr has been assigned to Berkeley 79 while age of Trumpler 11 has been estimated to be in the range of 100 to 250 Myr.