The principal way that a degenerate dwarf cools
is through the emission of neutrinos.  Unlike the
main-sequence stars, which generate neutrinos as part
of their thermonuclear generation of power, degenerate
dwarfs generate neutrinos from photons.  This process
allows degenerate stars to radiate away all of the energy
in their cores, giving them an inverted temperature structure
of a cold core surrounded by a hot outer layer.