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 (similar to 15'x15') J, H, and K band mosaic, deep near-infrared imaging at J, H, KI and nbL' bands of the central cluster region, and spectroscopic observations of 34 stars. By comparing the properties of the MonR2 cl uster with other star forming regions, we ultimately hope to lean how the properties and formation of stars of various masses are related to the local physical conditions. The K band star counts indicate that t he MonR2 cluster extends over a similar to 1.1 pc X 2.1 pc area with a FWPM cluster size of similar to 0.38 pc. Within this region the clust er contains similar to 309 stars brighter than m(k) = 14.5(m) and grea ter than or equal to 475 stars over all magnitudes with a central stel lar volume density of similar to 9000 stars pc(-3). We have further ex plored the properties of the cluster by using the spectroscopic and ph otometric 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 designe d to contain all stars with A(v) less than or equal to 11.3(m) and ste llar masses greater than or equal to 0.1 M. As a lower limit, 62% of t he stars in this sample contain a near-infrared excess at K and/or L b and. 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 star s in Taurus-Auriga. An initial reconnaissance of the stellar mass func tion suggests that the ratio of high to low moss stars in the extincti on-limited sample is consistent with the value expected for a Miller-S cale IMF. We do not find compelling evidence for mass segregation in t he extinction-limited sample for stellar masses less than or equal to 2 M., although the most massive star(similar to 10 M.) in the cluster appears to be forming near the cluster center. The properties of the M onR2 cluster are similar to other rich young clusters in the solar nei ghborhood, such as NGC 2024 and the Trapezium. (C) 1997 American Astro nomical Society.