Life cycle of a star

stages of a stars life the same size as the sun

1. protostar

2. main sequence star

3. red giant

4. white dwarf

5. black dwarf

stages of a stars life much bigger than the sun

1. protostar

2. main sequence star

3. red super giant

4. syupernova

5. neutron star or black hole

protostar

• cloud or dust and gas pulled together by gravitational attraction

• temperature is too low for fusion to take place

protostar to main sequence star

as the cloud becomes denser nuclei of hydrogen atoms and other light elements fuse together

energy is released

main sequence star

• the stable period of a star → the forces within it are balanced

• can maintain energy output for millions of years until the star runs out of hydrogen nuclei to fuse together

main sequence star to red supergiant

• star runs out of hydrogen nuclei to fuse together

• stars much bigger than the sun swell out to become a red supergiant

red supergiant

• helium and other light elements fuse to form heavier elements

• iron is heaviest elements element that can be formed

supernova to neutron star

explosion compresses the core of the star into a neutron star

supernova

• the star explodes

• conditions extreme enough for iron to fuse and produce heavy elements

• elements distributed throughout the universe

neutron star

a star believed to largely consist of neutrons

supernova to black hole

star collapses and keeps collapsing until it is no more than a point in space

black hole

an infinitely dense point in space (escape velocity is greater than the speed of light)

main sequence star to red giant

• star runs out of hydrogen nuclei to fuse together

• stars about the same size as the sun swell, cool down and turn red

red giant

helium and other light elements fuse to form heavier elements

red giant to white dwarf

• forces are insufficient for further fusion reactions

• the star collapses under the force of gravity

• it heats up and turns from red to yellow to white

white dwarf

a hot dense white star

white dwarf to black dwarf

• no further fuel available

• the star fades and goes cold

black dwarf

an inert lump in space