What happens when a main- sequence star exhausts its core hydrogen fuel supply?
A)The star becomes a neutron star.
B)The core shrinks while the rest of the star expands.
C)The entire star shrinks in size.
D)The core immediately begins to fuse its helium into carbon.

Question

Quizplus · Accepted Answer

When a main-sequence star exhausts its core hydrogen fuel supply, the core shrinks while the rest of the star expands. This is known as the helium flash and occurs when the core temperature becomes high enough for helium fusion to begin. The energy released causes the core to expand, decreasing the pressure and temperature, which stops the fusion. The core then contracts again, restarting the fusion process, causing the helium to fuse into carbon. This process continues until the core is mostly carbon and oxygen.

What Happens When a Main- Sequence Star Exhausts Its Core