Life and Death of a Star
Published on Jul 13, 2016
Stars, like everything else, go through life. They are born, grow up, get old, and eventually die. This photo diary outlines the life and death of a main sequence star.
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PRESENTATION OUTLINE
Life and Death
The story of your average main sequence star.
in the beginning
suns are formed from molecular clouds
Protostars
dense regions in the cloud collapse forming protostars
Main Sequence star
once enough matter has collapsed into the star is becomes a
they have limited lives
because stars have a limited supply of hydrogen
f*M/L
their life time is proportionate to the formual
Where "f" stands for
the fraction of the total mass of the star
The "M" stands for
the mass available for nuclear burning in the core
And "L" stands for
the average luminosity of the star in its M.S. time
The lifetime is sensitive to mass
because luminosity depends mostly on the mass of the star
and tend to die quickly
Really massive stars exhaust their core supply of hydrogen
live longer
whereas less massive stars and M.S stars tend to
Stars become red and more luminous
as they begin to exhaust their hydrogen and grow larger
this relationship
helps astronomers age the universe
As stars exhaust their supply of hydrogen
there is no longer a source of heat to protect against gravity
when our sun becomes a red giant
its atomosphere will consume the earth and everyone will die
The helium burning phases lasts about 100 mil years
until there is no more helium and the star becomes a red supergiant
When the sun becomes a red supergiant
its atmosphere will envelope jupiter
This brief stage of existence
lasts only a few 10 thousands years
Stars in this phase
lose a lot of their mass in an extremely powerful solar wind
Eventually the star loses all mass
and leaves behind a carbon core embedded in a nebula
Radiation from the core
ionizes the nebula of gas and forms a planetary nebula
the carbon core eventually cools
and becomes a white dwarf
