Properties of the Monoceros R2 Stellar Cluster

We present an extensive study of the stellar population of an embedded cluster in the MonR2 molecular cloud based upon a wide field (\about 15\arcmin x 15\arcmin) J, H, and K band mosaic, deep near-infrared imaging at J, H, K, and \NBL\ bands of the central cluster region, and spectroscopic observations of 34 stars. By comparing the properties of the MonR2 cluster with other star forming regions, we ultimately hope to learn how the properties and formation of stars of various masses are related to the local physical conditions. The K band star counts indicate that the MonR2 cluster extends over a \about 1.1 pc x 2.1 pc area with a FWHM cluster size of \about 0.38 pc. Within this region the cluster contains \about 309 stars brighter than m_K = 14.5\M\ and \more than or equal to 475 stars over all magnitudes with a central stellar volume density of \about 9000 stars pc(-3) . We have further explored the properties of the cluster by using the spectroscopic and photometric data to construct an extinction-limited sample of 115 stars in the central 0.77 pc x 0.77 pc region of the cluster that is designed to contain all stars with \AV\ <= 11.3\M\ and stellar masses >= 0.1 M\sun. As a lower limit, 62% of the stars in this sample contain a near-infrared excess at K and/or L band. The K band excess fraction may be as high as 72% if the accretion characteristics of the stars in the MonR2 cluster are similar to stars in Taurus-Auriga. An initial reconnaissance of the stellar mass function suggests that the ratio of high to low mass stars in the extinction-limited sample is consistent with the value expected for a Miller-Scalo IMF. We do not find compelling evidence for mass segregation in the extinction-limited sample for stellar masses \less than or equal to 2 M\sun, although the most massive star (\about 10 M\sun) in the cluster appears to be forming near the cluster center. The properties of the MonR2 cluster are similar to other rich young clusters in the solar neighborhood, such as NGC 2024 and the Trapezium.