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Stellar Birth
Jade J
Rachael H
Stages of Stars
• In the birth of a star there are seven
stages in it’s formation.
• A star's life is a constant battle against
gravity, and pressure support. That battle
begins as soon as a molecular cloud
begins to collapse into a protostar.
Interstellar Clouds
• Name given to an accumulation of gas,
plasma and dust.
• Denser than the average region of
interstellar medium.
Collapsing Cloud Fragment
• At this phase the cloud is very diffuse, so
heat is not trapped so the temperature
does not build up.
Fragmenting Ceases
• Several tens of thousands of years after
the collapse of the cloud the center
becomes opaque and the temperature
rises greatly.
• The cloud typically begins to shrink in size
and the appearance of a potostar can be
seen at the center.
Protostar
• At this stage the cloud begins to collapse
on its self increasing the temperature and
causing it to contract.
Protostar Evolution
• As the protostar moves past stage four it
moves closer to the main sequence.
• This stage is characterized by violent
surface activity and strong protostellar
winds.
Newborn Star
• The temperature has now become high
enough for thermonecular fusion to begin
• This results in somewhat lower luminosity
Main Sequence
• The star contracts a bit more and enters
into hydrostatic equilibrium.
• During the main sequence lifetime, the
star achieves stability by gas pressure.