Which of the following describes a star with a hydrogen-burning shell and an inert helium core?
A)It is a red giant that grows in luminosity until it dies in a planetary nebula.
B)It is a subgiant that gradually grows dimmer as its hydrogen-burning shell expands and cools.
C)It is a subgiant that grows in luminosity until helium fusion begins in the central core.
D)It is what is known as a helium-burning star,which has both helium fusion in its core and hydrogen fusion in a shell.

Question

Quizplus · Accepted Answer

This description matches a subgiant star, which increases in brightness as it evolves and expands, with a hydrogen-burning shell surrounding an inert helium core, until helium fusion ignites in the core.

Which of the Following Describes a Star with a Hydrogen-Burning