Sagot :
Answer:
the star's outer stellar layers expand and the core shrinks. At this point, the star becomes a Subgiant Star. The star's outer layers continue to expand and the star brightens.
Answer:
When the core hydrogen is used up and no more nuclear fusion occurs, the star's outer stellar layers expand and the core shrinks. At this point, the star becomes a Subgiant Star . The star's outer layers continue to expand and the star brightens.