Astronomy Colloquium / Fall 2006

November 21st

Prof. Keivan Stassun

Vanderbilt University

A Synthesis of Fundamental Issues in the Formation and Early Evolution of Low-Mass Stars and Brown Dwarfs

We report on recent progress and future prospects in three broad areas of research centered around the formation of low-mass stars and brown dwarfs. First, we discuss efforts to directly and accurately measure the fundamental physical properties (masses, radii, luminosities) of young low-mass stars and brown dwarfs as critical tests of theoretical star-formation models, including the recent discovery of the first brown-dwarf eclipsing binary. Second, we discuss the broad problem of magnetic field generation and X-ray production in these objects, highlighting results from the recent Chandra Orion Ultradeep Project. Third, we briefly discuss the problem of angular momentum evolution in these objects (i.e., the "angular momentum conundrum" of star formation), highlighting results from recent large surveys of stellar rotation in young clusters. Finally, we draw these recent results together to elucidate the physical interrelationships between stellar rotation, magnetic field generation, and stellar structure during the star-formation process.