A star leaves the main sequence when
A) nuclear fuel in its core can supply enough energy to stop its collapse.
B) it collapses, and its envelope becomes degenerate.
C) it stops fusing hydrogen in its core and starts to expand.
D) it forms planets.

Question

Quizplus · Accepted Answer

A star leaves the main sequence when it exhausts the hydrogen fuel in its core, causing the core to contract and the outer layers to expand, leading to the star becoming a red giant.

A Star Leaves the Main Sequence When