Life Cycle of a Star

• Stars begin life as a cloud of dust and gas called a nebula. Gravity causes the cloud of dust and gas to collapse. As the particles move faster, the temperature rises to millions of degrees celsius. If the temperature gets high enough, then hydrogen nuclei join together to form helium nuclei. This process is called nuclear fusion. Nuclear fusion releases a huge amount of energy. Stars can stay in the main sequence for a very long time. What happens next will depend on the size of the star.
• Stars are different colours dependent on their temperature (approximation, K = kelvin):

  • Blue stars = 18000K
  • Yellow stars = 6000K
  • Red = 4000K
• Stars have fuel (usually hydrogen, sometimes helium) that fuses (nuclear fusion) producing huge energy emissions in the form of Electro-Magnetic (EM) waves.