Red giant
Red giant is a phase of stellar evolution in which a star expands and cools after exhausting hydrogen in its core. It is characterized by increased luminosity and a large radius relative to main-sequence stars.
Red giants are discussed in astrophysics, stellar evolution, and observational astronomy.
Status
Red giants are observed across a range of stellar masses and compositions. Models of their internal structure, energy transport, and subsequent evolutionary paths continue to be refined.