As a white dwarf cools its radius will not change because
A)pressure due to nuclear reactions in a shell just below the surface keeps it from collapsing.
B)pressure does not depend on temperature for a white dwarf because the electrons are degenerate.
C)pressure does not depend on temperature because the white dwarf is too hot.
D)pressure does not depend on temperature because the star has exhausted all its nuclear fuels.
E)material accreting onto it from a companion maintains a constant radius.

Question

Quizplus · Accepted Answer

Pressure in a white dwarf is due to the electrons present in it becoming degenerate. This means that the electrons are packed so tightly that they cannot be compressed further, and thus their pressure does not depend on temperature. As the white dwarf cools, the electrons become more tightly packed, but their pressure remains the same, and so the radius of the white dwarf does not change.

As a White Dwarf Cools Its Radius Will Not Change