Transcript Life Cycle of a Star

Life Cycle of a Star
Waves, 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.
2.
3.
4.
5.
6.
When the core is trying to fuse Fe
No more energy can be gained
Fusion stops, no more outward pressure
Gravity Wins … the collapse starts
After the collapse … rebound … material explodes out
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 Holes
A 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
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
Neutron Star Formation