Science Colloquium
Brown Dwarfs: From First Principles
Lorne Nelson
Bishop's University
Friday, April 8, 2005
12:30 - 1:20 PM
Hamilton Room 301
I review the history of Brown Dwarf astronomy and show why Brown Dwarfs are needed to bridge the gap between ordinary stars and giant gas planets such as Jupiter. By invoking the Virial Theorem I show how the formation of stars and Brown Dwarfs differ. In the former case, the contraction of the hydrogen gas cloud is halted by thermal pressure while in the latter case the contraction is halted by elecron degeneracy pressure (similarly for a White Dwarf). Finally I show how the signature of Lithium in the atmospheric spectra of these objects is a definite indicator that the object is a Brown Dwarf as opposed to a star.
