Red Giant

Giant and highly luminous red star in the later stages of stellar evolution after it has left the main sequence. These red stars have a relatively cool surface whose core has burned most of its hydrogen. Red giants lose parts of their atmospheres and thus provide new elements into interstellar space such as carbon.These stars are found on the upper-right hand side of the Hertzsprung-Russell diagram (high luminosity, temperature ~2000-3000 K, diameter 10-100 Rsun). The Sun will become a red giant in ~5 billion years.

Some or all content above used with permission from J. H. Wittke.