Professor Charles J. Lada
Harvard-Smithsonian Center for Astrophysics
clada@cfa.harvard.edu
4:15-5:15 Tuesday
May 6,
2003
Abstract
Once formed, the subsequent life history of a star is essentially predetermined by one parameter, its mass at birth. Consequently knowledge of the frequency distribution of stellar birth masses and the variation in space and time of this distribution is of fundamental importance for understanding the evolution of stellar systems from clusters to galaxies. The functional form of this initial mass function (IMF) is not predicted by stellar evolution theory or by existing theories of star formation. The IMF must be determined directly from empirical data. Young embedded stellar clusters provide important new laboratories for IMF measurements. For example, studies of such clusters enable a determination of the IMF over a range of mass significantly greater than previously possible, a range that now extends deep into the substellar mass regime to masses near the deuterium burning limit. In this colloquium I will discuss how infrared studies of embedded clusters are leading to significant improvements in our knowledge of the functional form and universality of the IMF and the implications of this new knowledge for our understanding of the star formation process.