STARS: BIRTH, LIFE AND DEATH

There are 3 types of stars that you need to be familiar with...

Low Mass stars Intermediate Mass

stars High Mass stars

1. LOW MASS STARS Also known as Red Dwarf

Stars

Characteristics... Start and stay relatively

small

Exist as dim, cool red dwarfs

Burn hydrogen fuel very slowly, lasting up to 100 billion years

Method of Death/Burn Out Eventually become very hot (but small)

dim, white dwarfs and quietly burn out

Sirius B

2. INTERMEDIATE MASS STARS Example: our Sun

Characteristics... Burns hydrogen fuel faster

than low mass stars, lasting about 10 billion years

Expands into a red giant after a long period of stability

Method of Death/Burn Out Red giant sheds most of its material into space

Collapses in on itself, becoming a small, dim, white dwarf

Keeps cooling until it becomes a black dwarf a dense, dark body made up of mostly carbon and oxygen

3. HIGH MASS STARS Characteristics... 12+ times the mass of our Sun

Burn fuel faster than the other 2, lasting about 7 billion years

Become supergiants when they’ve used all their fuel

Method of Death/Burn Out Supergiants collapse on

themselves, forming supernovas

There are 2 possible endings from there: Neutron Star Black Hole

Cassiopeia A

1. Neutron Stars Remaining core of supernova will

eventually collapse on itself, forming a neutron star

  Neutron Star: (average)

starts out more than 1million km across but collapses into a sphere only 10km wide

2. Black Holes Happens to stars 25+ times the size

of the Sun Called black because nothing (not even light) can escape it

so dense that it creates a massive gravitational pull

Evidence: materials pulled towards black holes emit electromagnetic radiation, which can be measured Gravity from black holes effects passing stars/galaxies Computer models show howit can distort light from distantstars

STAR SIZES Stars can vary greatly in size Although our Sun is an average size,

many of the stars we see in the night sky are up to 3000 times as large as the Sun.