A Red Supergiant is a massive star that has exhausted the hydrogen in its core and expanded significantly. These stars are among the largest in the universe, often exceeding 1,000 times the radius of the Sun. They are typically found in the later stages of stellar evolution and can be several hundred thousand times more luminous than the Sun. Red supergiants are characterized by their reddish color, which results from their cooler surface temperatures, usually between 3,000 and 4,000 Kelvin. Famous examples include Betelgeuse and Antares. Eventually, these stars will end their life cycle in a spectacular explosion known as a supernova.