Imagine comparing a 1.2 solar mass white dwarf to a 1.0 solar mass white dwarf. Which of the following must be true?
A) The 1.2 solar mass white dwarf has a larger radius.
B) The 1.2 solar mass white dwarf has a smaller radius.
C) The 1.2 solar mass white dwarf has a higher surface temperature.
D) The 1.2 solar mass white dwarf has a lower surface temperature.
E) The 1.2 solar mass white dwarf is supported by neutron degeneracy pressure; the 1 solar mass white dwarf is supported by electron degeneracy pressure.

Question

Quizplus · Accepted Answer

The radius of a white dwarf is inversely proportional to its mass. Therefore, the 1.0 solar mass white dwarf has a larger radius than the 1.2 solar mass white dwarf. The surface temperature of a white dwarf is dependent on its radius and luminosity, so we cannot make any assumptions about the surface temperature based on mass alone. The type of degeneracy pressure supporting the white dwarf is determined by the mass at which electron degeneracy pressure is overcome, which is approximately 1.4 solar masses. Therefore, neither of the white dwarfs in this comparison is supported by neutron degeneracy pressure.

Imagine Comparing a 1