A low-mass main-sequence star's climb up the red giant branch is halted by
A) the end of hydrogen shell burning.
B) the beginning of helium fusion in the core.
C) electron-degeneracy pressure in the core.
D) instabilities in the star's expanding outer layers.
E) an explosion that destroys the star.

Question

Quizplus · Accepted Answer

The climb up the red giant branch is halted when helium fusion begins in the core, a process known as the helium flash.

A Low-Mass Main-Sequence Star's Climb Up the Red Giant Branch