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Stars are started by
NEBULA: Cloud of
gas and dust

Hydrogen makes up
97% of a Nebula.
Helium makes up 3%
of a Nebula
All other elements
makes up less than
1% of a Nebula
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
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A high mass and low mass
star starts off the same way.
Near the end of the death
of the High Mass Star runs
out of hydrogen it swells
and grows cooler, different
than a low mass star. The
evolutionary difference is
that the High Mass Star
passes through a pulsating
Yellow Giant phase before
it becomes a Red Giant. At
the end of a low mass star
the helium stars too burn
out and it goes back to the
core
http://library.thinkquest.org/3103/nonshocked/topics/highmassstar/h
ighmassstars.html
http://astronomyonline.org/Stars/LowMassEvolution.asp
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A Protostar is a baby
star or pre-star
Notes the formation of stars
A Protostar is
surrounded by a lot
of gas and dust that
blocks the light, but
allows through large
amounts of far
infrared.
http://www.daviddarling.info/encyclopedia/P/protostar.html

This is when the
Protostar gains enough
mass to begain fusion.
All main sequence
stars fuse Hydogen
Notes life cycle of a star

Stars live out the majority
of their lives in a phase
termed of the Main
Sequence. Once getting
nuclear fusion, stars shine
energy into space
http://aspire.cosmic-ray.org/labs/star_life/starlife_sequence.html
http://library.thinkquest.org/05aug/00108/mainsequence_frameset.htm
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A neutron star is about
20 km in diameter and
the mass of about 1.4
times that of the Sun.
This means that a
neutron star is so
bigger that on Earth,
one teaspoonful
would weigh a billion
tons. Its small size and
high density, a neutron
star possesses a
surface gravitational
field.
http://imagine.gsfc.nasa.gov/docs/science/know_l1/pulsars.html
http://www.universetoday.com/wpcontent/uploads/2008/05/foxneutronartwork.jpg
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White dwarfs form
from the collapse of
stellar cores which
nuclear fusion has
stopped, and are
exposed to space
following the loss of
the old star's bloated
outer envelope,
typically as a
planetary
nebulahttp://www.daviddarling.info/encyclopedi
a/W/whitedwarf.html
http://www.daviddarling.info/encyclopedia/W/whited
warf.html

Star with the mass of
25 to 50 times the sun
from black holes
after a supernova.
the left over core of
the star is so dense
that it causes a
gravitational
collapse.
Act two high mass stars
http://en.wikipedia.org/wiki/Black_hole
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A white dwarf cools
off over trillions of
years until it no
longer emits light
Act one small to medium mass
http://www.daviddarling.info/encyclopedia/B/blackdw
arf.html