A band on the Hertzsprung-Russell diagram representing stars fusing hydrogen into helium. Stars spend the majority of their lifetime on the main sequence. The Sun is a main-sequence star and will remain so for about 5 billion more years.
A massive, luminous sphere of hot gas held together by gravity, generating energy through nuclear fusion. Stars range fr...
A luminous giant star that has exhausted its core hydrogen. The outer layers expand and cool, giving a reddish appearanc...
A stellar core remnant of electron-degenerate matter, Earth-sized but with a mass comparable to the Sun. The final state...
Dive deeper into main sequence and related concepts on Cosmos Observatory.