Transcript STARS and GALAXIES

STARS and GALAXIES
“Twinkle Twinkle Little Star, How I Wonder
What You Are”
Stars
• A large ball of gas held together by gravity
that produces tremendous amounts of
heat and light.
• Some stars are very old and the size of
planets or moons, and some no longer
emit radiation (no light).
Energy Production
• Most of the tremendous amounts of
energy produced by most stars is a result
of nuclear fusion.
Nuclear Fusion
• The sun converts atomic nuclei into
energy.
• The energy of nuclear fusion of most stars
is eventually radiated to space as types of
electromagnetic energy.
Classification System (ESRTpg.15)
• Classification of stars is based on their
temperature and luminosity in relation to
our Sun.
• Absolute Luminosity (brightness)Measures how bright a star is in relation to
the sun, if all the stars were the same
distance from the Earth.
• Apparent Luminosity- The brightness we
see when we look at the stars. Depends
on the star’s distance and magnitude
(strength).
Temperature
• A star’s temperature
is indicated by its
color. Stars change
from blue to red as
their temperature
decreases.
STAR TYPES
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Main Sequence- average star (Sun)
Giants- 10x size of Sun
Supergiants- 100-1000x size of Sun
White Dwarfs- small, planet sized
Black Dwarfs- “dead” white dwarf, no energy
Neutron Star- collapse, dense core of a star
Black Hole- extremely dense remnant of a star
Stellar Evolution
Nebula