Life Cycle of a StarWaves, Atoms and Space

Black Dwarf

Stage 1

Protostars

Protostars

• 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 2

Main sequence star

Main Sequence Star

• Burning Hydrogen • E.g. Our sun• Sequence lasts for

about 10 000 million years

• Our sun is about half way through it’s main sequence

Stage 3

Red Giant

Red 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.

Planetary Nebula

• Following the Red Giant Stage• (a) Planetary Nebula (gas)• (b) White Dwarf

Stage 4

White Dwarf• The car engine is turned off …• Hood is still hot

White 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 5

Black Dwarf

Black 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!

At least four times bigger (you don’t need to know about these

for your exams)

Stage 4(for a big star)

Red Supergiant

Stage 5(for a big star)

Supernova

1. When the core is trying to fuse Fe2. No more energy can be gained3. Fusion stops, no more outward pressure4. Gravity Wins … the collapse starts5. After the collapse … rebound … material explodes out6. Heavy elements formed during these final stages

Supernova!

• The largest and most powerful explosions in the universe.

• The red supergiants literally blow themselves apart!

Supernova Remnant

Supernova

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

Stage 6(for a big star … after the rebound)

Black hole

Black 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.

Supermassive Black HolesA supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses. Most—and possibly all—galaxies are inferred to contain a supermassive black hole at their centers. In the case of the Milky Way, the SMBH is believed to correspond with the location of Sagittarius A*

Video Clip

Neutron Stars

Neutron Star Formation

A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type (II) event. Such stars are composed almost entirely of neutrons, which are subatomic particles without net electrical charge and with slightly larger mass than protons