NGC 7419: a young open cluster with a number of very young intermediate mass pre-MS stars

Abstract

We present a photometric and spectroscopic study of the young open cluster NGC 7419, which is known to host a large number of classical Be stars for reasons not well understood. Based on CCD photometric observations of 327 stars in UBV passbands, we estimated the cluster parameters as, reddening (E(B V)) = 1.65±0.15 mag and distance = 2900 ± 400 pc. The turn-off age of the cluster was estimated as 25± 5 Myr using isochrone fits. UBV data of the stars were combined with the JHK data from 2MASS and were used to create the near infrared (NIR) (J H) vs (H K) colourcolour diagram. A large fraction of stars (42%) was found to have NIR excess and their location in the diagram was used to identify them as intermediate mass pre-MS stars. The isochrone fits to pre-MS stars in the optical colour-magnitude diagram showed that the turn-on age of the cluster is 0.3 –3 Myr. This indicates that there has been a recent episode of star formation in the vicinity of the cluster.