For low-mass main-sequence stars in hydrostatic equilibrium, at any interior radius there exists a balance between the downward gravitational force at that radius and:
A) the pressure from a degenerate electron core
B) the convective force of material rising from the interior
C) the energy released from fusion reactions in the core
D) the outward gas pressure from the material inside that radius
E) the energy released by fusion reactions in a shell surrounding the degenerate core

Question

Quizplus · Accepted Answer

The balance between the downward gravitational force and the outward gas pressure at any interior radius is what allows a low-mass main-sequence star to maintain hydrostatic equilibrium. This is because the gas pressure is what pushes against the force of gravity and keeps the star from collapsing in on itself. Choices A, C, and E don't apply to low-mass main-sequence stars, which don't have degenerate cores or fusion reactions in their cores or shells. Choice B might apply to other types of stars, but it's not relevant to the case of low-mass main-sequence stars.

For Low-Mass Main-Sequence Stars in Hydrostatic Equilibrium, at Any Interior