Jovian Planet Moons and Rings

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Jovian Planet Moons and Rings

• Each planet has multiple moons and seem like
  mini-solar systems
• Moons are mostly made of ice, so quite soft and
  can be more active than similar sized rocky
  planets/moons
• Rings are made of individual small particles,
  orbiting like micromoons

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A Mini-Solar System

• Many moons, 4 big ones found by Galileo, another
  12 over 350 years from the Earth
• Dozens more by spacecraft imaging on
  fly-bys/orbits most are captured asteroids
• Jupiter also has a narrow, faint ring system

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JUPITER The Galilean Moons

• Io and Europa -- smaller, rockier, differentiated
• Ganymede and Callisto -- further, bigger and
  icier Ganymede is the biggest Moon in SS

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Jupiter Surrounded by Moons

• Named after lovers of Jupiter from mythology
  Galilean all have synchronous orbits
• Almathea inside them (181,000 km from center
  260 km diameter) -- discovered in 1892 by Barnard
• 4 even smaller moons found inside Galilean (found
  by Voyagers and early Galileo)
• 4 moons around 11,000,000 km out e and i high
  captured asteroid(s) known from Earth
• 4 more captured moons around 23,000,000 km out
  these have retrograde orbits.
• A total of 63 known in 2009 -- largest number of
  confirmed moons

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IO most active object in SS

• a 422,000 km D 3640 km M 1.22 MMoon
• Multicolored surface yellow, orange, red, brown,
  and white sulfur S compounds
• Rocky mantle Fe/FeS core ? 3.5 g/cm3
• Strong tidal flexures P 1.77d 1/2 P(Europa)
  1/4 P(Ganymede) ? forced heating from resonant
  orbit
• Sulfur volcanoes blasting out particles Very
  smooth, young ( lt 1 Myr) surfaceflows Fills up
  Jupiter's plasma torus ionized S atoms.

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Io and its Volcanoes
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EUROPA Icy Oceanic?

• a 671,000 km D 3130 km M
  0.65 Mmoon ? 3.04 g/cm3
• Icy crust kms thick, temporary cracks Colored
  areas mostly mineral rich ices Probable 100 km
  thick ocean -- LIFE EXISTS(ED) THERE ????
• Surface lt 100 Myr old new ice replacing old
• Less heating by tidal flexure than Io, but still
  a good bit warmed up from resonant orbits

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Europa cracked, oozy ice
Liquid water ?on surface?
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GANYMEDE King of the Moons

• a 1,070,000 km D 5270 km
• M 2.02 MMoon
• ? 1.93 g/cm3 ? very thick ice layer
• Rocky mantle, Fe/FeS core Many craters, many
  old ones survive Grooved terrain ? plate
  tectonics at 3 Gy in the past
• Only satellite with a magnetic field

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Ganymede
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CALLISTO Deadest of All Biggies

• a 1,880,000 km D 4800 km M 1.46
  Mmoon ? 1.83 g/cm3 ? mixture
  of rock and ice
• More craters, fewer faults, than Ganymede