The Hertzsprung-Russell (H-R) Diagram

The Hertzsprung-Russell Diagram is extremely useful in summarizing stellar evolution. The diagram clearly shows that most stars follow the main sequence. As stars evolve, they eventually become unstable and begin to shed their outer layers. Once the outer layers are shed, the star grows outward quickly. This creates a red giant and supergiant. A long time after its birth, the star will begin to burn out and become a dwarf and then black hole. This is all described graphically in the H-R diagram.