Jovian Planets

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Jovian Planets

• Rulers of the Solar System

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Properties
Mass (kg) Radius (km) Average Density (kg/m3) of Moons Mag. field (?1) Rotation Period (days) Surface Temp. (K) Surface Gravity (?1)
Jupiter 1.9 x 1027 71,000 1330 16 14 0.41 124 2.5
Saturn 5.7 x 1026 60,000 710 18 0.7 0.43 97 1.1
Uranus 8.7 x 1025 26,000 1240 21 0.7 -0.69 58 0.91
Neptune 1.0 x 1026 25,000 1670 8 0.4 0.72 59 1.1

• Most of Jupiter and Saturn and about half of
  Uranus and Neptune are made of Hydrogen and Helium

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Voyager
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Energy

• With no surface, no surface modification
  processes
• No craters
• No volcanoes
• No tectonics
• No erosion
• These are big planets
• Big planets have lots of internal energy
• With no endogenic surface processes, where does
  the energy go?

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Bands Storms
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Bands

• Differential rotation poles take longer to
  rotate than equator

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Storms
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The great red spot
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SL9
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Interiors
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Magnetosphere
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Uranus orbit
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Planetary Rings
Composition Size
Jupiter Dust Small grains
Saturn Water ice lt house size
Uranus Carbonaceous Large paricles
Neptune dark, unknown unknown, small

• All the Jovian planets have rings
• These are not solid, but composed of millions of
  tiny particles of ice and dust
• Rings have structure gaps and spokes

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Rings
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Ring structure
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What makes the rings?
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Shepard moons
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Planetary rings Why?

• Left to itself, a ring will slowly spread out due
  to gravitational interactions
• Rings are bounded by the stronger gravity of
  larger bodies The planet itself and some of the
  larger and nearby moons
• Some bounds are due to gravitational resonances,
  others due to the direct action of sheparding
  satellites
• The origin of the rings is unknown either a
  failed satellite or a broken satellite
• A reason is known the tidal stability limit at
  2.5 times the radius of the body. Interior to
  this, 2 touching particles will be pulled apart
  by the planets gravity
• Why dont inner planets have rings? Gravitation
  perturbations by the Sun will cause any small
  particles to spiral into the planets on a
  relatively short time scale.