Degeneracy pressure is the source of the pressure that stops the crush of gravity in all the following except
A)a brown dwarf.
B)a white dwarf.
C)a neutron star.
D)a very massive main-sequence star.
E)the central core of the Sun after hydrogen fusion ceases but before helium fusion begins.

Question

Quizplus · Accepted Answer

The crush of gravity in a very massive main-sequence star is stopped primarily by thermal pressure due to the high temperatures and densities present in the core. Once the star exhausts its nuclear fuel and begins to contract, the degeneracy pressure of the electrons and eventually the neutrons becomes important in supporting the structure of the resulting compact object (such as a neutron star or white dwarf). However, for a massive main-sequence star that undergoes a supernova explosion, the pressure from the shock wave generated by the explosion is what ultimately halts the collapse.

Degeneracy Pressure Is the Source of the Pressure That Stops