As a low-mass main-sequence star runs out of fuel in its core, it grows more luminous. How is this possible?
A) It explodes.
B) It begins to fuse helium in the core.
C) The core expands as it runs out of fuel.
D) The core shrinks, bringing more hydrogen fuel into the burning region.
E) Convection takes place throughout the interior, bringing more fuel to the core.

Question

Quizplus · Accepted Answer

As the core of a low-mass main-sequence star runs out of hydrogen fuel, it contracts under gravity, which increases the temperature and pressure in the surrounding shell, causing hydrogen shell burning and increasing the star's luminosity.

As a Low-Mass Main-Sequence Star Runs Out of Fuel in Its