Transcript Stages of a star.pps

Birth of a Star
The stages of how a star’s life begins.
By: McKenna F
Stage One- The Interstellar Cloud
• Area of interstellar dust
and gas that is more
concentrated than the
surrounding interstellar
medium.
• All stars form from these
clouds of dust and gas,
called nebulae.
• In the first million years
of its life, the star is
hidden from view inside
the nebulae it formed in.
Stage Two- Clouds Collapse
• Spontaneous Star Formation
– When the molecules inside these
clouds of interstellar dust and
gas become unstable the cloud
starts to develop a gravitational
pull.
• Triggered Star Formation
–In either situation the gases and dust of the
nebula start to collapse and compress.
– Clouds can also start to become
unstable because of the
interference other electric forces
(like exploding supernovae)
located near them in space.
Stage Three- Protostar
• A protostar is a
collection of dust
and gas, joined
together by this
compression and
gravitational pull.
• All these
molecules are
moving and
releasing energy.
• This release of
energy generates
heat and light,
causing the
protostar to glow.
• Protostars are
often hard to see
because they are
still hidden in the
nebula but can be
using infrared
cameras.
Stage Four- Accretion
Protostars exist where the
gravitational pull is equal to the
pressure of the gases.
When the gases start
to compress, the
combined effect
generates a higher
gravitational pull.
This gravitational pull
attracts more molecules,
fragments and bits of
interstellar medium.
Evolution of A
Protostar
•
The protostar starts at a
temperature of about
100 Kelvin
• After 1.000 years this
temperature has risen to
about 4,250 Kelvin.
• It takes about 100,000
years to go from 4,250 to
4,500 Kelvin.
• After another 100,000
years the temperature is
5,000 Kelvin.
•
Stage Five
During this time the
brightness heightened
at 100 times that of the
sun, but as the star
grows the brightness
drops.
• Over the next 20 million
years protostar's
developments to where
it equals the Sun in
luminosity and its size
becomes fixed at about
1.6 million km in
diameter.
• It only took what 30
million years…
Stage SixNuclear Fission
• While the protostar is
attaining dust, gas, and
increasing in pressure, size
and gravitational pull the
core to become very
concentrated and very
dense.
• When to many hydrogen
atoms are too close
together at very high
temperatures, they go
through nuclear fusion and
fuse together.
• Once this process starts, the
protostar has become and
actual star.
Stage Seven- Main Sequence Star
• During this the stage of nuclear fusion
(about 90% of the star’s life) it is classified
as a main sequence star.
Sources
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http://gallery.spitzer.caltech.edu/Imagegallery/image.php?image_name=sig06-021
http://library.thinkquest.org/21008/data/star/birth.htm
http://sscws1.ipac.caltech.edu/Imagegallery/subcat.php?cat=Astronomical%20Images&
subcat=Star%20Formation
http://outreach.physics.utah.edu/labs/star_life/starlife_proto.html
http://en.wikipedia.org/wiki/Star_formation
http://en.wikipedia.org/wiki/Circumstellar_disc
http://www.geocities.com/CapeCanaveral/Launchpad/1364/Stars.html