Abstract:
JHK magnitudes have been determined for 18 stars in the field of NGC 654. Study of the interstellar extinction law in the cluster direction indicates an anomalous distribution of interstellar grains causing more extinction in U and B pass-bands compared to that obtained from the color excesses E(V-J), E(V-H) and E(V-K) using a normal reddening law. This implies a small shift in the grain-size distribution towards smaller than normal-sized particles. Patchy distribution of interstellar matter seems to be responsible for the nonuniform extinction in the cluster region.
