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STAR LIFE
CYCLE
The Dramatic Birth, Life, and Death
of a Star
Nebula
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A nebula is a cloud of dust and gas, composed primarily of
hydrogen (97%) and helium (3%). Within a nebula, there are
varying regions when gravity causes this dust and gas
Proto Star
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Within a nebula, there are varying regions when gravity
causes this dust and gas to “clump” together. As these
“clumps” gather more atoms (mass), their gravitational
attraction to other atoms increases, pulling more atoms
into the “clump.”
The Main Sequence
We now have reached STAR status. To be a star it
much reach 6 million degrees C, and be able to do
nuclear fusion. Stars spend most of their life as a
main sequence star.
Nuclear fusion
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The reaction which occurs in stars.
Through the combining of atoms of
elements, such as hydrogen, a heavier
element is created along with the release of
a large amount of energy.
Main Sequence Star Continued
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The more massive stars the heavier the star the
heavier the elements.
Which is where most of the heavy elements in the
universe are made.
Throughout this whole process is that battle
between gravity and gas pressure, known as
equilibrium.
It’s crucial to keep this battle in your mind when
trying to understand how stars live and die.
Heavy element
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During the process of fusion in stars, atoms
of hydrogen combine with other hydrogen
atoms or different elements to form heavier
elements.
Red Giant Star
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A Red Giant Star is a main sequence star
that is not longer in equilibrium. There is a
greater outward force than an inward force.
Red Giants can increase a hundred times
its size.
Question?
Choose from the following hypotheses regarding
length of star life:
A. The bigger a star is, the longer it will live.
B. The smaller a star is, the longer it will live.
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Now, for whichever hypothesis you chose, Write
a 1-3 sentence explanation for why you think this
is so.
Nova/ Super Nova
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Once the star becomes unstable the star
will eventually explode which is called a
Nova or Super Nova depending how
massive the star is.
The Bigger the Star the Bigger the
Explosion!!
The Bigger the Star the Shorter it will live.
What happens to the exploded star?
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After the Nova or Super Nova the gases and heavy
elements produced through nuclear fusion are sent into
space and become a new nebula were new stars and
planet can form.
There is also a left over core, and depending on the
mass of the star depends on the name of size of the
object produced.
The left over centers after the Nova or
Super Nova
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Low Mass Stars ( Like our Sun): Become
White Dwarfs then Black Dwarfs.
Massive Stars: Become Neutron Stars
Super Massive Stars: Become A Black
Hole.
From Birth to Death…
The Star Life Cycle Compared to
Human Life Cycle.