Lifecycle of a star

• What determines the type of lifecycle that a star goes through?

  The size of the star
• What do small stars like the Sun become?

  Black dwarf stars
• What do large stars become?

  Neutron stars
• What do the largest of stars become?

  Black holes
• How do all stars begin?

  Clouds of dust and gas are drawn together by gravity to form a protostar and then a main sequence star
• What happens during the main sequence in small stars?

  Hydrogen fuses together to create helium
• What happens during the main sequence in large stars?

  Hydrogen fuses together to form helium and lithium
• Describe the life cycle of a star as it ages?

  More of its mass is converted into energy by nuclear fusion. As its mass decreases, the outward forces become larger than the force of gravity. The star expands and become a red giant / red super giant . As it cools and the hydrogen fuel is used up, the outward forces reduce , which causes the star to collapse inwards from gravity and increase in temperature , and begin to fuse helium and lithium.
• What do the largest stars explode as ?

  They explode as a supernova
• What do supernovas do?

  Explode to release large amounts of energy and scatter the material of a star into space
• Fusion reactions lead to an equilibrium between what?

  The gravitational collapse of the star, and the expansion of the star due to fusion energy
• The image below shows the lifecycle of a star about the same size as the sun (Remember that a nebula comes before the protostar) - this can be remembered with the acronym N.P.M.G.W.B (Naughty People Might Get Wild Beatings)

  
• The image below shows the lifecycle of stars much bigger than the sun (Remember that a nebula comes before the protostar) - this can be remembered with the acronym N.P.M.SG.S.B/N (Nice.People.Must.Surely.Get.Sugary.Bicsuits/Nuts)