stars

• Stages in the life cycle of a star

  • Protostar
  • Main Sequence Star
  • Red Giant
  • Supernova
  • Neutron Star
  • Black Hole
  • White Dwarf
  • Black Dwarf
• Formation of a protostar

  1. Cloud of dust and gas forms

  2. Gravity pulls the dust and gas together to form a protostar

  3. Protostar gets denser and particles collide

  4. Nuclear fusion begins, releasing energy to heat the core
• Main Sequence Star


  • Stars about the size of the Sun
  • Stable period where nuclear fusion occurs
• Transition from Main Sequence to Red Giant

  1. Hydrogen begins to run out

  2. Star expands and cools, becoming a red giant

  3. Fusion of helium and heavier elements occurs in the core
• Transition from Red Giant to Supernova

  1. Star becomes unstable

  2. Ejects outer layers of dust and gas

  3. Leaves behind a hot, dense solid core - a white dwarf
• White Dwarf


  • Emits less and less energy over time
  • Eventually becomes a black dwarf when it no longer emits significant energy
• Transition from Supernova to Neutron Star or Black Hole

  1. Exploding supernova throws outer layers into space

  2. Leaves behind a very dense core called a neutron star

  3. If the star is massive enough, it becomes a black hole - a super dense point in space that even light cannot escape
• Stars and their life cycles produce and distribute all naturally occurring elements