The Stellar Populations of Deeply Embedded Young Clusters: Near-Infrared Spectroscopy and Emergent Mass Distributions

The goal of this thesis is to test the following hypothesis: the initial distribution of stellar masses from a single "episode" of star formation is independent of the local physical conditions of the region. In other words, is the initial mass function (IMF) strictly universal over spatial scales d M* > 1.0 solar mass) to low-mass (1.0 solar mass > M * > 0.1 solar mass) stars in order to compare these mass distributions to the Miller-Scalo IMF. As an example of this analysis we present a study of the embedded cluster associated with the NGC2024 nebula. Although this cluster contains an enhanced number of intermediate mass stars, we cannot distinguish the distribution of stellar masses from the field star IMF. A detailed comparison between the stellar luminosity functions of the embedded clusters associated with the NGC2024 cluster and the embedded population found in the Ophiuchus cloud cores suggests that it is unlikely they were drawn from the same parent population. After finding the evolutionary states and accretion properties of both clusters to be similar, we interpret the difference in stellar luminosity functions as a difference in their emergent mass distributions. Synthesizing results for NGC 2024 and Ophiuchus with those from other studies of embedded clusters, we arrive at the following conclusions: i) the emergent mass distributions of most of the embedded young clusters considered are consistent with having been drawn from the Miller--Scalo IMF; and ii) there is a hint that regions of high central stellar density contain a greater proportion of intermediate mass stars.