Download Life Cycle of Stars

Life Cycle of Stars
Constellation Project
Information
How Stars Begin…
• Inside vast clouds of
gas and dust floating
in space, gravity
causes the denser
areas to pull together,
or coalesce.
• These clouds are
called nebulae.
Crab Nebula
Cat’s Eye Nebula
As the nebula starts to spin…
• Gravity compresses
the gas and dust into
a spinning disk with a
bulge in the middle.
• A warm protostar
forms as the center
collapses under its
own gravity.
• The protostar radiates
heat and ejects matter
from its poles.
• Eventually, fusion
begins in hydrogen
gas at the core and the
star begins its life.
The disk either disperses or forms
planets
Not all stars are the same:
• Stars exist that are
significantly larger
and significantly
smaller than our sun.
• Not all stars have
planets.
• Some stars are older
than our sun and
some are younger.
The Hertzprung-Russell Diagram
• Built to show
the relationship
between
absolute
magnitude,
luminosity,
classification
and effective
temperature of
the stars.
Many variations exist..
• Notice the spectral
classes at the bottom
and their relationship
to surface
temperature.
• This version also
includes the red and
blue giant regions.
• Be sure to compare
your stars to the Sun.
How Stars End
• Stars burn until they use all their nuclear
fuel.
• Different size stars evolve differently.
• The larger a star, the hotter, brighter and
shorter lived it is.
A Star the Size of Our Sun
• Burns for 10 billion
years
• Star exhausts its
hydrogen and swells
into a red giant.
• Core collapses.
Nuclear reaction
blows off the star’s
surface.
Blown-off gases form a
glowing nebula.
The core of the star collapses into
a white dwarf star.
• When our Sun becomes a red giant its size will
interfere with the Earth’s orbit.
• We’re about 4 billion years from when that will
occur.
A Star 10 x the size of our Sun
• Burns out in 20 million
years
• Bright, hot, blue star
uses up its hydrogen
fuel, swells into a red
supergiant.
• It is 5000 x more
luminous than our
Sun (see comparison
in the two pictures)
• When nuclear
reactions cease, the
core collapses and
the star explodes in
a brilliant
supernova.
• If the star explodes
with enough force,
much of its mass is
hurled into space,
leaving behind a
small, dense
neutron star.
A Star 30 x the size of the Sun
• These stars can exhaust their fuel in as
little as 1 million years.
• This large star is one of the most luminous
in the universe.
• It expands into a red supergiant and ends
in a powerful supernova explosion.
• Its huge core
collapses past the
neutron star stage
and becomes a black
hole
• This is a dense,
heavy structure
whose gravity is so
strong that not even
light can escape from
the interior.
An artists representation
• I love this picture of a
black hole seemingly
devouring a nearby
star.
• Notice the X-ray
emissions of the black
hole showing how
matter is changed into
energy.
Works Cited
• Rand McNally New Concise Atlas of the
Universe, “The Universe Explained;
The Life and Death of Stars”