Dark Nebula Cores and the Origin of Stellar Masses

Detailed knowledge of the initial distribution of stellar masses at birth (the IMF) and how this quantity varies through space and time is necessary to predict the evolution of all stellar systems from star clusters to galaxies. Yet the origin of stellar masses remains one of the most fundamental unsolved problems of astrophysics. Stars form in the dense cores of dark nebulae, but little is understood about the detailed physical properties of these cores prior to star formation and even less is understood about their origin. Yet both these issues are critically linked to understanding the origin of stellar masses and the IMF. In this colloquium I will relate current knowledge concerning the functional form and universality of the IMF to exciting new results concerning the physical nature of dense cores on the verge of star formation. I will argue that these results suggest that the distribution of initial stellar masses derives directly from the distribution of dense core masses which itself may have its origins in a process of simple thermal fragmentation in a pressurized medium. The initial distribution of stellar birth masses produced by star formation may therefore be the result of the interplay of only a few very basic and measurable physical processes.

Speaker: Charles Lada (Harvard-Smithsonian Center for Astrophysics)

All 2008 Spring Colloquia talks are held on Wednesdays in the STScI John N. Bahcall Auditorium at 3:30 p.m. preceded by tea at 3:15 p.m.

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