Life Cycle of a StarLife Cycle of a Star

Stage 1Stage 1

ProtostarsProtostars

ProtostarsProtostars

• Huge clouds of gas (hydrogen) in which stars are made.

• Many thousands of times bigger than our solar system

• As the clouds collapse stars are born in them

Stage 2Stage 2

Main sequence starMain sequence star

Main Sequence StarMain Sequence Star

• E.g. Our sun• Sequence lasts for

about 10 billion years• Our sun is about half

way through it’s main sequence

Stage 3Stage 3

Red GiantRed Giant

Red GiantRed Giant

• As the sun runs out of hydrogen the outer layers of the sun will become cooler

• They will also expand massively.

• The Earth (along with Mercury, Venus and Mars) will be swallowed up.

Stage 4Stage 4

White DwarfWhite Dwarf

White DwarfWhite Dwarf

• Gravity will cause the red giant to collapse

• The sun is now much cooler and it collapses into a small white star

• It still has the same mass as the original sun!

Stage 5Stage 5

Black DwarfBlack Dwarf

Black DwarfBlack Dwarf

• The sun cools more and more

• Eventually it will become a black mass emitting no light

• It will then spend the rest of eternity drifting silently through space

Stars bigger than our Sun!Stars bigger than our Sun!

At least four times biggerAt least four times bigger

Stage 4Stage 4(for a big star)(for a big star)

Red SupergiantRed Supergiant

Stage 5Stage 5(for a big star)(for a big star)

SupernovaSupernova

Supernova!Supernova!

• The largest and most powerful explosions in the universe.

• The red supergiants literally blow themselves apart!

SupernovaSupernova

• All the atoms we are made from came originally from these giant supernova explosions.

Stage 6Stage 6(for a big star)(for a big star)

Black holeBlack hole

Black holeBlack hole

• After the supernova a huge mass is left behind.

• There is so much mass its gravity prevents even light from leaving it

• Black holes can suck in nearby stars and solar systems.

• Luckily there are no black holes any where near our sun!