Transcript Stars - Mc Guckin Science

Other Solar
System Bodies
Asteroids
• Millions located between
Mars and Jupiter
• Irregularly shaped composed of silicate
rock, some made of metal rich materials
• Some have orbits that cross Earth’s path
Comets
• Made of dust and ice (dirty snowball)
• A comet forms a tail due to the suns solar
wind
• The tail always points away from the sun
Meteors
• Made of dust and rock
• They burn up when entering atmosphere
Meteorite
• Made of dust and rock
• Can strike the Earth
Stars
Characteristics of Stars
• Temperature & Color
– The color of a star indicates the T of the
star
– Stars are classified by T
• Decreasing T (bright to dim)
• O, B, A, F, G, K, M [Oh Be A Fine Girl, Kiss
Me ]
Guy
http://www.seasky.org/cosmic/sky7a01.html
Types of Stars
Classification
Temperature
Color
20,000- 60,000 K
Blue
10,000 – 30,000 K
Blue-white
7,500 – 10,000 K
White
6,000 – 7,500 K
Yellow-white
5,000 – 6,000 K
Yellow
3,500 – 5,000 K
Orange
2,000 – 3,500 K
Red
Hertzsprung-Russell Diagram
http://www.dustbunny.com/afk/stars/lifecycle/hrdiagram.gif
Close ups of white dwarf stars
Life Cycle of Stars
http://www.seasky.org/cosmic/sky7a01.html
Life Cycle of Stars
• Begin their lives as clouds of dust and gas called
nebulae
• Gravity may cause the nebula to contract
• Matter in the gas cloud will begin to condense
into a dense region called a protostar
• The protostar continues to condense, it heats
up. Eventually, it reaches a critical mass and
nuclear fusion begins.
• Begins the main sequence phase of the star
• Most of its life is in this phase
Carina nebula
Life Cycle of Stars
Life span of a star depends on its size.
– Very large, massive stars burn their fuel much
faster than smaller stars
– Their main sequence may last only a few
hundred thousand years
– Smaller stars will live on for billions of years
because they burn their fuel much more
slowly
• Eventually, the star's fuel will begin to run
out.
Life Cycle of Stars
• It will expand into what is known as a red
giant
• Massive stars will become red supergiants
• This phase will last until the star exhausts
its remaining fuel
• At this point the star will collapse
Dust
around a
supergiant
Life Cycle of Stars
• Most average stars will blow away their
outer atmospheres to form a planetary
nebula
• Their cores will remain behind and burn as
a white dwarf until they cool down
• What will be left is a dark ball of matter
known as a black dwarf
Planetary nebula
• Crab nebula
Orion nebula
Life Cycle of Stars
• If the star is massive enough, the collapse will
trigger a violent explosion known as a
supernova
• If the remaining mass
of the star is about 1.4
times that of our Sun,
the core is unable to
support itself and it will collapse
further to become a neutron star
supernova
Life Cycle of Stars
• Matter inside the star will be compressed
so tightly that its atoms are compacted into
a dense shell of neutrons.
• If the remaining mass of the star is more
than about three times that of the Sun, it
will collapse so completely that it will
literally disappear from the universe.
• What is left behind is an intense region of
gravity called a black hole
Recap
1. Nebula
red giant
dwarf
main sequence star
white dwarf
black
2. Nebula
red dwarf
black dwarf
white dwarf
3. Nebula
massive main sequence
supergiant
supernova
neutron star or black hole
Relative Size: Sun vs. Planets
Sun vs. Other Stars
Binary star
size: 100 of our suns