AST 341 Lecture Notes - Lecture 18: Solar Mass, White Dwarf, Degenerate Matter
25 Dec 2016
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Document Summary
We now turn our discussion to the evolution of the remnant central star into a cool white dwarf. Once the thin shell of burning helium is exhausted, what is left is a degenerate c-o core. With its supply of energy exhausted, the star is supported against gravitational collapse by the degenerate pressure of its own electrons. At the beginning of its evolution, although it doesn"t have a nuclear energy source in its interior any longer, the white dwarf is very hot. It loses energy at the surface, which is replenished by thermal energy from the interior (thermal energy of the heavy particles, the ions). Because of the energy loss the star therefore must slowly cool down. Unlike the situation for non-degenerate stars, the pressure does not change when a degenerate star cools since the star is balanced by the degenerate electron pressure which does not change with decreasing temperature.
