Astronomy/Stellar Evolution

For 2012, the Astronomy event will focus on stellar evolution and type Ia supernovae.

Stellar Life Cycle
The life cycle differs between stars depending on their mass. Normal-mass stars begin in stellar nurseries, and some matter condenses to create a protostar. This gains more mass until fusion begins, when it becomes a main-sequence star. Then, as it uses up its store of energy, it grows to be a giant star by the end of its lifetime. Once it uses its entire store, it collapses into a planetary nebula and later a white dwarf. Larger stars are similar, except they begin with more mass and grow to supergiants. At the end of their lifetime, they can explode in a massive explosion known as a supernova and/or collapse into a neutron star or a black hole.

Smaller mass stars (red dwarves) don't become giants. They just collapse to form a dim black dwarf. No black dwarfs have been found yet, as red dwarfs have average life spans of about 200 billion years.