The origin of low mass stars.
Recent evidence indicates that most low mass stars in the Galaxy (< 5 M [symbol: see text]) form alongside massive stars in clusters embedded in giant molecular clouds. Once their parental gas is removed, the fate of these clusters is to disperse and blend into the field population of the galactic disk. The distribution of stellar masses in the solar neighborhood, called the Initial Mass Function, is discussed in the context of the origin of low mass stars. Arguments based on the production rate of field stars are presented that point to giant molecular clouds as the primary birth sites for low mass stars. The role of observations of molecular clouds at millimeter and infrared wavelengths in confirming this picture is reviewed. Millimeter-wave observations have revealed that molecular clouds consist of low-density gas interspersed with high-density cores. Near-infrared images of these clouds indicate that stars form preferentially in these cores, with the number of young stars roughly scaling with the mass of the core. Molecular-line and near-infrared observations which characterize star formation in the nearest giant molecular cloud complex in Orion are presented. The implications for the Sun forming in a cluster environment are briefly discussed.
Wilking
B A
BA
Department of Physics and Astronomy, University of Missouri-St Louis 63121, USA.
D055580:Astronomical Phenomena; D001256:Astronomy; D005118:Extraterrestrial Environment; D016082:Solar System; D013055:Spectrophotometry, Infrared; D013995:Time; D014894:Weights and Measures