Life Cycle of a Star

Notes using the foldable

Life Cycle of a StarNebula

Protostar

Red Dwarf Yellow Star Blue Giant

Red Giant

White Dwarf

Black Dwarf

Red Super Giant

Supernova

Black Hole Neutron Star

The smaller the stars, the longer the life because they use up their fuel more slowly

How long a star lives depends on the mass

Nebula

• All stars begin as parts of nebulas

• A large cloud of gas and dust

• large amount of gas in a small volume, very dense

Protostar

• The 1st stage of a star’s life• A contracting cloud of gas and dust• Pressure and heat start nuclear fusion

Different Masses mean different types of stars

Mass of star

How long a star lives depends on how much mass it has

A small mass star uses less fuel so it lasts longer so . . .

The smaller the mass the longer it lasts

Red Dwarf

• A small mass star

• Can last up to 200 billion years

Yellow Star

• A medium mass star

• Our sun is a yellow star

• Lives for 10 billion years

Blue Giant

• A large mass star

• 10-15 times larger than the sun

• VERY hot

• Short lives because they have used up a lot of fuel

Red Giant

• The star runs out of fuel

• outer parts expand, then the core shrinks

• It turns red as it is cooling

• This phase will last until the star exhausts its remaining fuel.

• The pressure of the nuclear reaction is not strong enough to equalize the force of gravity so the star will collapse.

Red Super Giant

• The star runs out of fuel• The core shrinks and the outer parts

expand• It turns red as it is cooling • This phase will last until the star exhausts

its remaining fuel. • The pressure of the nuclear reaction is not

strong enough to equalize the force of gravity so the star will collapse.

White Dwarf

• No more fuel left

• Faint glow from left over energy

• Outer parts drift out into space

• Small blue white hot core is left

• About the size of Earth

Supernova

• As the core shrinks, pressure increases

• Results in an explosion

Black Dwarf

• When the white dwarf stops glowing it is dead\very dense

Black Hole

• Remains of explosion collapse into a black hole

• Most large mass stars turn into black holes

Neutron Star

• After explosion some material left behind

• Forms a neutron star

• Dense and small