Photometric and kinematic studies of open star clusters. II. NGC 1960 (M 36) and NGC 2194

Abstract

We present CCD photometry and proper motion studies of the two open star clusters NGC 1960 (M 36) and NGC 2194. Fitting isochrones to the colour magnitude diagrams, for NGC 1960 we found an age of t=16 Myr and a distance of roughly d=1300 pc and for NGC 2194 t=550 Myr and d=2900 pc, respectively. We combined membership determination by proper motions and statistical field star subtraction to derive the initial mass function of the clusters and found slopes of Gamma=-1.23 +/- 0.17 for NGC 1960 and Gamma=-1.33 +/- 0.29 for NGC 2194. Compared to other IMF studies of the intermediate mass range, these values indicate shallow mass functions.