What is the life cycle of a star?

Nebula [cloud of dust and gas] Protostar [Helium nuclei formed from particles colliding creating a high temperature] Main Sequence Star [Star enters a long stable period generally several billions of years] Then either: Red Giant [Hydrogen runs out and star swells] White dwarf [Becomes unstable and ejects outer layer of dust and gas leaving core] Black Dwarf [White dwarf cools down, emits less energy] Or: Red Super Giant [Hydrogen runs out and star swells to bigger than Sun] Supernova [Star undergoes more fusion and expands and contracts until it explodes] Neutron Star [Exploding supernova leaves a very dense core] or Black Hole [Exploding supernova leaves a super dense point in space]