Why does a star grow larger after it exhausts its core hydrogen?
A)The outer layers of the star are no longer gravitationally attracted to the core.
B)Hydrogen fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward.
C)Helium fusion in the core generates enough thermal pressure to push the upper layers outward.
D)Helium fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward.
E)The internal radiation generated by the hydrogen fusion in the core has heated the outer layers enough that they can expand after the star is no longer fusing hydrogen.

Question

Quizplus · Accepted Answer

Hydrogen fusion in a shell outside the core generates enough thermal pressure to push the upper layers outward, causing the star to expand. This occurs when the core hydrogen is exhausted, and hydrogen fusion continues in a shell surrounding the now inert core.

Why Does a Star Grow Larger After It Exhausts Its