Word Bank: Mass, massive, Neutron, Main Sequence, Luminosity, Temperature, Brightness, Stable, Red Giants, Super Giants, Cepheids, Supernova, Black Holes, Neutrons, White dwarf, HR Diagram, Stable

Stars can be classified according to their surface and their (how brightly they shine)
Most stars fall on the Hertzberg-Russell (HR) diagram.
These stars are relatively .
About 90% of stars are and . which shine brightly but at a low temperature, so with a large volume.
are very hot and small, and don't shine and very brightly.
A group of unstable stars called appear between the main sequence and the red giants.
What happens next to a star depends on its birth .
Very high mass stars can become and they finally either stars or