Download largest and most massive planets [Figure 12

Chapter 12: Jupiter and Saturn
Jupiter Visuals
jupiter.jpg
jupiterearthspot_comparison.jpg
Saturn Visuals
saturn-rings1.jpg
planets_size.avi
vital statistics
Jupiter
Saturn
Orbital distance
5.2 AU
9.5 AU
Orbital period
11.9 years
29.5 years
Rotation period
9.9 hrs, differential
10.7 hrs, differential
Axial tilt
3º
27º
Known Satellites
16
18
Mass
318 x MEarth
95 x MEarth
Radius
11.2 x REarth
9.5 x REarth
Density
1.33
0.69
Surface Gravity
2.54 g
1.08 g
Global Temp
125 K
95 K
Escape Velocity
60 km/s
36 km/s
(earth’s 11.2 km/s) 1
largest and most massive planets [Figure 12-5]
Jupiter takes up 70% of planetary matter
low density => mostly hydrogen and helium
differential rotation [12_6.mov]
equator and poles rotate at different rates!
→ fluid bodies
rapid rotation + fluid body → flattened shape
Voyager 2 Missions [Fig 12.2, 1]
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Saturn and Jupiter: “surface” features
zonal winds and belt features [Figure 12-6,8(jupiter), 7,9(saturn) ]
similar to Earth’s jet streams
Great Red Spot of Jupiter [Figure 12-6,11]
present since at least 1665 (Cassini)
a high pressure system (direction of rotation)
other storms:
smaller white spots last decades [Fig 12-6,12]
dark spots last years [fig 12.13].
Some smaller high pressure systems also appear on Saturn[fig 12.14]
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Atmospheres of Jupiter and Saturn
mostly (99.9%) Hydrogen and Helium
Jupiter has 3x as much Hydrogen as Helium, by mass
Approximately Solar mix
Saturn has Helium deficit (7 to 1 ratio)
Convection Cells [figure 12-17] produce belts on Jupiter
Temperature banding: Jupiter (IR [figure 12-15] ) and Saturn (radio [figure 12-16])
Temperature decreases with altitude (increases towards interior)
[Figure 12-18]
Clouds: ammonia, ammonium hydrosulfide ice and water
coloration [Figure 12-19, 20 (artist conception based on galileo data)]
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Interiors: [Figure 12-21]
Gradual change from gas to liquid
High pressures (Jupiter ~ 50 Mb, Saturn ~10Mb) and Temperatures
(~20,000 K)
→ “exotic” states of matter
→ metallic Hydrogen (fluid conductor)
Density indicates some heavier materials
rock, metals and ice at core
Interiors hot, planets radiate more than they absorb
self luminous (in infrared)
Internal energy source!
Jupiter: leftover from initial contraction
initially had ~1% of sun’s brightness (but 1/4 Sun's temp)
Saturn: initial contraction energy essentially used up
current source: helium settling in core
explains Helium deficit
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Magnetospheres [figure 12-22]
strong magnetic fields
dynamo: rapid rotation + convection in liquid conductor
(metallic hydrogen)
field rotates with planet, dragging trapped ions along rotation
magnetodisk: plasma (lifted by rotation) around equator
Aurora [figure 12-23]
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Rings (both Jupiter and Saturn have ring systems)
[figure 12-24, 25, 27, jupiter: figure 29,30]
individual particles in independent orbits (not solid [figure 12-26])
Structure [figure 12-31,32,34,35]
resonances: partial explanation of structure
orbital period of particles an integer fraction of the orbit of one of the
moons [figure 12-33 12_31.mov]
collisions “flatten” rings [figure 12-28]
most of rings appear within Roche Distance [figure 12-36]
Roche Distance:
closest distance an object can orbit a planet without being torn apart by
tidal forces (~2.5 planet radius) →possible ring origin
rings should dissipate, must be (relatively) young
particles either work inward and hit atmosphere or work outward and
escape into space.
Saturn's moon Enceladus is 'feeding' Saturn's largest ring
tidal force heating induced volcanism [PIA08386_enceladus_r.jpg]
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Comet Shoemaker-Levy (remnant) impact (JULY 1994)
[ http://www2.jpl.nasa.gov/sl9/ ]
from: http://nssdc.gsfc.nasa.gov/planetary/planets/
Missions to Jupiter
Past Missions
* Cassini - NASA/ESA Mission to Saturn via Jupiter
* Galileo Orbiter - NASA Mission to Jupiter
* Galileo Probe - NASA Mission to Jupiter
* Voyager 1 - NASA Mission to Jupiter and Saturn
* Voyager 2 - NASA Mission to Jupiter, Saturn, Uranus, Neptune, and beyond
* Ulysses - NASA/ESA Mission to study the solar wind via Jupiter
* Pioneer 10 - NASA Jupiter flyby (1973)
* Pioneer 11 - NASA Jupiter flyby (1974)
Future Missions
* Jupiter Icy Moons Orbiter (JIMO) - NASA Proposed Europa, Ganymede, and Callisto Orbiter (2015)
* Juno - NASA New Frontiers Jupiter Polar Orbiter under study
Missions to Saturn
Current and Past Missions
* Cassini - NASA/ESA Mission to Saturn
* Huygens - NASA/ESA Mission to Saturn's satellite Titan
* Voyager 1 - NASA Mission to Jupiter and Saturn
* Voyager 2 - NASA Mission to Jupiter, Saturn, Uranus, Neptune, and beyond
* Pioneer 11 - NASA Saturn flyby (1979)
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