Question

what is Red- giant? ​

Answer 1

Answer:

A very large star of high luminosity and low surface temperature. Red giants are thought to be in a late stage of evolution when no hydrogen remains in the core to fuel nuclear fusion.

Answer 2

A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around 5,000 K (4,700 °C; 8,500 °F) or lower.