Once a star uses up all its fuel it evolves to a white dwarf. However, low mass stars can only burn hydrogen and not helium. Higher mass stars burn helium, and stop at carbon. Still higher can burn carbon. Explain how these higher mass stars can burn other elements in their cores.
Stars burn fuel through thermonuclear fusion.
The shells of supernova shine by radioactive decay or fission. Explain the difference between fission and fusion. Describe the difference between gas and dust in the interstellar medium. Where would you expect to find short period variable stars in the Galaxy and why.