Stellar process
The Red-Giant Branch
When a star exhausts the hydrogen in its core, fusion moves to a shell around an inert helium core. The envelope swells enormously and cools to a red glow, and the star climbs the red-giant branch — brightening as it ascends until helium ignites at its tip.
Stars, stages & concepts
Across stellar astrophysics
Knowledge connections
- Associated withMain-Sequence Evolution
- Associated withTip of the Red Giant Branch
- Associated withThe Helium Flash
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.