the lifecycle of a star

• stars that are the same size as the sun

  • begins as a mains sequence star
  • hydrogen begins to run out
  • the outward force is less than gravitational force
  • gravity causes the sun to collapse inwards
  • this increases the temperature
  • helium fuse to create heavier elements
  • the star expands to form a red giant
  • at some point it stops fusing helium
  • the star shrinks to a white dwarf
  • the star cools down
  • it stops releasing energy and turns into a black dwarf
• stars bigger than the sun

  • hydrogen runs out and the star expands to a red super giant
  • helium nuclei fuse to form heavier elements
  • nuclear fission stops
  • it explodes this is called a super nova
  • higher temperatures cause elements heavier than iron
  • the remains of the super nova forms either
  • a neutron star where the neutrons are densley packed
  • or a black hole which has really strong gravity