The Jovian Planets, Part II

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The Jovian Planets,Part II

• Saturn

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SATURNThe God of Agriculture
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Physical Data

• Diameter 119,871 km (9.41 Dearth)
• Mass 5.69x1029 g (95.1 Mearth)
• Density 0.70 g/cm3 (lighter than water!)
• Rotation Period 10.66 hours
• Tilt of Axis 26.7o
• Surface Temperature 103 K (-274o F)

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Physical Data

• Orbital Semi-Major Axis 9.54 AU
• Orbital Period 29.46 years
• Orbital Inclination 2.5o
• Orbital Eccentricity 0.056
• Surface Gravity 1.17 Earth gravity
• Satellites 18 known
• Magnetic Field yes

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Saturns Interior
ATMOSPHERE

• Outer three layers are similar to Jupiters
• The exact composition of the core of Saturn is
  still unknown

LIQUID MOLECULAR HYDROGEN
METALLIC HYDROGEN
ICE?
ROCK?
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Saturns Atmosphere

• 94 Hydrogen
• 6 Helium
• Small amounts of
• Methane
• Ammonia
• Phosphine
• Ethane
• Acetylene

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Saturns Atmosphere
CLOUDS

• Composed of methane and ammonia
• Saturn is surrounded by an orange haze which
  masks the cloud -top features
• Saturns belts are therefore less noticeable

False color image shows Saturns bands
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Saturns Atmosphere

• WINDS
• Unlike Jupiter, all go in the same direction
  (east)
• The equatorial jet reaches speeds of 1,100 mph!
  (Fastest winds on Jupiter are 335 mph)

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Saturns Atmosphere

• FEATURES
• Ovals - cyclonic features like Great Red Spot on
  Jupiter
• They dont last long
• Biggest ovals seen on Saturn are only 1/10
  as big as the Great Red Spot

The White Spot of 1994
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Saturns Atmosphere

• Hot Surface Temperature
• Like Jupiter, Saturn radiates 2.5x as much heat
  as it receives from the Sun
• Saturn is two times farther away from the Sun
  than Jupiter, and receives 1/4 as much sun light,
  so Saturns interior is less hot
• Saturns internal heat is due to heavy element
  diffusing toward the interior

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Saturns Magnetic Field

• Detected by Pioneer spacecraft
• Between the size of Earth and Jupiters magnetic
  field (0.5 Gauss)
• Magnetic axis is almost aligned with rotation
  axis (0.7o tilt)

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Saturns Rotation Periods

• Differential rotator like Jupiter
• Rotation Period is 10h02m at equator
• Rotation Period is 1 hour longer at 60o latitude
• Radio Period 10h39m22s
• Spin so fast, Saturn is very oblate (flat)

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Saturns Ring System

• There is a gap between the A and B ring called
  Cassinis Division
• Ring particles are made of mostly ice
• Average particle size is about 10 meters

CASSINIS DIVISION
SATURN
A
F
G
E
B
C
D
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Saturns Ring System

• Spokes
• Magnetically levitated dust which is rotating
  with the magnetic field
• This dust is about the size of cigar smoke

m
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Saturns Ring System

• Shepherd Satellites
• Small moons in the rings gravitationally interact
  with wandering ring particles and return them to
  the ring, thus preserving the ring.

Shepherd Satellites Prometheus and Pandora
sheperding the F ring
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Saturns Moons

• A total of 18 have been discovered thus far
• Co-Orbital Satellites
• As a trailing co-orbital satellite overtakes the
  leading satellite, they gravitational forces make
  the moons trade places

1 2 3
4 5
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Saturns Moons

• TITAN
• Saturns largest moon
• Only 2 smaller than Ganymede, so is the second
  largest moon in the solar system
• Has a thick nitrogen atmosphere
• Surface Pressure 1.6 atm

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Saturns Moons

• MIMAS
• Has an impact crater that is 1/3 the diameter of
  the satellite
• Biggest impact Mimas could have taken and still
  survived

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Saturns Moons

• PHEOBE
• Discovered in 1898
• First retrograde satellite known in the solar
  system
• Most likely a captured satellite
• Saturns outermost moon

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Saturns Moons

• Iapetus
• Is sweeping dark dust from Pheobe
• Like most moon it is in synchronous rotation
• Its leading face is therefore 5x dimmer than its
  trailing face

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Saturns Moons

• Hyperion
• Only satellite in the solar system that is not in
  synchronous orbit
• Not spherical
• It is the sixteenth moon out and is 286 km in
  diameter