Red giant

A red giant is a luminous giant star of low or intermediate mass, in a late phase of stellar evolution.

The appearance of a red giant ranges from yellow-orange to red.

These large, relatively cool stars, are formed when a main sequence star runs out of hydrogen and begins fusing helium. Some red giants were considered B class stars.

Types of Red Giants:

• Most commonly, red giants are still fusing hydrogen into helium, in a shell surrounding an inert helium core.
• A type known as "red-clump" continue to fuse helium into carbon in their cores via the triple-alpha process.
• "Asymptotic-giant-branch" types contain still-burning helium inside a carbon–oxygen core, and a hydrogen-burning shell just beyond that.

See main page: Types of Stars