Comets

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Comets

• Sara Matchulat
• Amanda Riddle

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• Comet an icy member of the solar system,
  traveling in an elliptical orbit around the Sun,
  which follows the basic laws of physics.
• Shine only in when near the Sun in space,
  comets are only the nuclei.

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Comets History

• Greek kometes / Latin cometa meaning
  long-haired
• Aristotle atmospheric phenomena
• Brahe parallax of the comet of 1577
• Newton the comet of 1680 and the orbit of
  comets
• Halley the orbits of comets

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Basic Structure

• Nucleus
• Coma
• Tails (Ion and Dust)
• Hydrogen Cloud

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Nucleus

• Irregular surface and shape
• Low density and surface gravity
• Made mostly of water ice and stony, metallic
  solids
• Dirty Snowball model by Fred Whipple in 1950

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The Coma

• Develops near the sun
• Sun melts the ice which allows dust particles to
  escape and expand
• Dust reflects sunlight

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The Tails

• Develop when traveling near the Sun
• Gas/Ion Tail ions that have interacted with
  solar winds
• Often a straight line behind the comets nucleus
  away from the sun
• Dust Tail dust particles are pushed out by
  radiation pressure from the sun
• Follow the comets nucleus in a curved path

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Hydrogen Cloud

• Hydrogen atoms that have expanded outward

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Deep Impact

• NASA mission between January and August 2005 with
  impact on July 4th, 2005
• Comet Tempel 1
• Sent to study the interior of a comet

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Composition of a Comet

• Tells us about the origin of the solar system
• Believed to be left over material from the
  formation of the planets
• Comprised of a rocky core surrounded by water ice
  and other frozen gases interspersed with dust
  particles

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Short-period or Periodic Comets

• Obits around the sun lasting only a few years or
  decades
• About 150 catalogued
• I.e. 1P/Halley 76.0 years
• 14P/ Wolf 8.2 years
• 2P/Encke 3.3 years
• 55P/Tempel-Tuttle 33.2 years
• Usually less elliptical orbits
• Found in Kuiper Belt

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Long-period Comets

• Extremely elliptical orbits
• Found in Oort Cloud
• Orbits take as long as 30 million years