THE LIFE OF A STAR
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THE LIFE OF A STAR http://hubblesite.org/newscenter/archive/ releases/nebula/2004/26/
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Transcript of THE LIFE OF A STAR
THE LIFE OF A STAR
http://hubblesite.org/newscenter/archive/releases/nebula/2004/26/
What will determine how a star lives out its life?( Examine the diagram.)
How much mass a star has.
What is mass?
How much matter is present in a given object.
(A) First Contraction:Gravity pulls together gas and dust which
eventually forms a stable star.
(1) Nebula (http://www.meade.com/gallery/images/orion_nebula.jpg)
Nebula:
A cloud of gas and dust where stars are born!
(2) Protostarhttp://physics.ship.edu/~mrc/pfs/108/node3.htm
Protostar:The first star formed where fusion begins
and energy is radiated outward.
Fusion:
The combining of two atomic nuclei which produces large amounts of energy/heat.
Example:
hydrogen + hydrogen = helium + energy
(3) Main Sequence
http://physics.ship.edu/~mrc/pfs/108/node3.htm
Main Sequence Star:
A middle-aged stable star which uses hydrogen as a fuel source.
Example: The Sun
http://physics.ship.edu/~mrc/pfs/108/node3.htm
(B) Second Contraction:
The outflow of energy from the fusion of hydrogen is less than the gravity keeping
the star together.
(C) Expansion:
The star starts to fuse helium and this creates the release of energy which is greater than the force of gravity.
(4) Red Giant
Red Giant http://wonderquest.com/images/2005-03-10-red-giant-star.jpg
Red Giant:
A large, bright, cool star which uses helium as a fuel source.
(D,E,G) Third Contraction
The supply of helium is depleted which causes the force of gravity to be greater than the energy released from the star due to fusion.
If the amount of matter in the star is average (up to 8 times the Sun’s mass),it will follow Path #1 to form a White Dwarf (5).
A White Dwarf: a small,dim,hot star.
A White Dwarf will eventually burn out and form a Black Dwarf (6).
White Dwarf
http://www.astronomy.mps.ohio-state.edu/npogge/Ast162/unit3/extreme.html
http://leonatopo.splinder.com/archive/2005-12
Nova:
A star that changes in brightness and has an explosion which removes some of its outer layers.
If a star is more massive than the sun ( 8 to 20 times greater ),during the 3rd Contraction, the outer layers will violently explode and implode, throwing matter into space as well as creating a dense core.
This phenomenon is called a: Supernova (F,H).
Supernova:
A violent explosion which occurs within the outer layers of a massive collapsing star which throws matter into space as well as implodes matter into the middle forming a dense core.
The end result:
A Neutron Star (7)
Neutron Star http://solarsystem.nasa.gov/multimedia/gallery/neutron.jpg
Neutron Star:
A star that forms from a collapsed star which had 8 to 20 times the mass of our Sun.
If the star is an extremely massive star
(greater than 20 Sun masses), during
the 3rd Contraction, a supernova will occur which will create a collapsed star so dense, visible light will not be able to leave its gravitational pull. This is called a --?
Black Hole (8) http://brokekid.net/img/blackhole.jpg
Black Hole:
A collapsed star so dense that visible light cannot escape its gravitational pull.
