life cycle of stars

(the Sun right now is a main sequence star)

what are the stages of the life cycle of a star bigger than the Sun?

1. nebula

2. protostar

3. main sequence star

4. red super giant

5. supernova

6. neutron star OR black hole

what are the stages of the life cycle of a star around the same size as the Sun?

1. nebula

2. protostar

3. main sequence star

4. red giant

5. white dwarf

6. black dwarf

what is a nebula?

• cloud of dust and gas

• where stars initially form

how is a protostar formed?

• gravity pulls dust and gas together

• star becomes denser

  • temperature rises

  • more particles collide

• high enough temperature = hydrogen nuclei undergoes nuclear fusion

  • forms helium nuclei

• helium nuclei gives out lots of energy

what is the main sequence star?

• star in a long, stable period

• outward pressure from nuclear fusion (to expand star) = gravity pulling everything in

what happens to the star as hydrogen begins to run out?

• swells into red giant

  • if it is the size of the Sun

• swells into red super giant

  • if it is bigger than the Sun

what occurs in the red giant or red super giant?

• fusion of helium and other elements

• heavier elements created in the core

after becoming a main sequence star why does the star become red?

surface cools