Photometric study of Galactic open cluster NGC 2129, NGC 1502 and King 12

Abstract

We present deep Johnson UBV and Cousins RI CCD photometry of three young open clusters, namely, NGC 2129, NGC 1502 and King 12 reaching down to V ∼ 22 mag. For the first time, we have reported optical CCD data for King 12. Fun- damental parameters for these clusters have been determined by comparing colour- colour and colour-magnitude diagrams (CMDs) with the theoretical models. The clus- ter radii have been estimated to be 3.3, 1.7 and 3.9 pc for NGC 2129, NGC 1502 and King 12 respectively. The reddenings E(B-V) have been determined to be 0.77±0.05, 0.68±0.05 and 0.63±0.05 while the corresponding distances have been found to be 2.1±0.1, 1.0±0.1 and 2.5±0.1 kpc respectively. The ages of the clusters have been obtained after fitting theoretical stellar evolutionary models for solar metallicity Z = 0.019 isochrones with the observed CMDs. This gives an age of 10.0±0.1 Myr for all the three clusters. The analysis shows that there is differential interstellar reddening in the direction of all clusters.