1. The Jovian Planets, Part II Saturn

2. SATURN The God of Agriculture

3. Physical Data u Diameter: 119,871 km (9.41 D earth ) u Mass: 5.69x10 29 g (95.1 M earth ) u Density: 0.70 g/cm 3 (lighter than water!) u Rotation Period: 10.66 hours u Tilt of Axis: 26.7 o u Surface Temperature: 103 K (-274 o F)

4. Physical Data u Orbital Semi-Major Axis: 9.54 AU u Orbital Period: 29.46 years u Orbital Inclination: 2.5 o u Orbital Eccentricity: 0.056 u Surface Gravity: 1.17 Earth gravity u Satellites: 60 as of 2011 u Magnetic Field: yes

5. Saturn’s Interior METALLIC HYDROGEN ATMOSPHERE LIQUID MOLECULAR HYDROGEN u Outer three layers are similar to Jupiter’s u The exact composition of the core of Saturn is still unknown ROCK? ICE?

6. Saturn’s Atmosphere u 94% Hydrogen u 6% Helium u Small amounts of: Methane Ammonia Phosphine Ethane Acetylene

7. Saturn’s Atmosphere u Composed of methane and ammonia u Saturn is surrounded by an orange haze which masks the cloud -top features u Saturns belts are therefore less noticeable CLOUDS: False color image shows Saturn’s bands

8. Saturn’s Atmosphere WINDS: u Unlike Jupiter, all go in the same direction (east) u The equatorial jet reaches speeds of 1,100 mph! (Fastest winds on Jupiter are 335 mph)

9. Saturn’s Atmosphere FEATURES: u Ovals - cyclonic features like Great Red Spot on Jupiter u They don’t last long u Biggest ovals seen on Saturn are only 1/10 as big as the Great Red Spot The White Spot of 1994

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

11. Saturn’s Magnetic Field u Detected by Pioneer spacecraft u Between the size of Earth and Jupiter’s magnetic field (0.5 Gauss) u Magnetic axis is almost aligned with rotation axis (0.7 o tilt)

12. Saturn’s Rotation Periods u Differential rotator like Jupiter u Rotation Period is 10 h 02 m at equator u Rotation Period is 1 hour longer at 60 o latitude u Radio Period: 10 h 39 m 22 s u Spin so fast, Saturn is very oblate (flat)

13. Saturn’s Ring System u There is a gap between the A and B ring called “Cassini’s Division” u Ring particles are made of mostly ice u Average particle size is about 10 meters B AFGE CD CASSINI’S DIVISION SATURN

14. Saturn’s Ring System Spokes: u Magnetically levitated dust which is rotating with the magnetic field u This dust is about the size of cigar smoke m

15. Saturn’s Ring System Shepherd Satellites: u 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

16. Saturn’s Moons u A total of 18 have been discovered thus far Co-Orbital Satellites: u As a trailing co-orbital satellite overtakes the leading satellite, they gravitational forces make the moons trade places 1 2 3 4 5

17. Saturn’s Moons TITAN: u Saturn’s largest moon u Only 2% smaller than Ganymede, so is the second largest moon in the solar system u Has a thick nitrogen atmosphere u Surface Pressure: 1.6 atm

18. Saturn’s Moons MIMAS: u Has an impact crater that is 1/3 the diameter of the satellite u Biggest impact Mimas could have taken and still survived

19. Saturn’s Moons PHEOBE: u Discovered in 1898 u First retrograde satellite known in the solar system u Most likely a captured satellite u Saturn’s outermost moon

20. Saturn’s Moons Iapetus: u Is sweeping dark dust from Pheobe u Like most moon it is in synchronous rotation u It’s leading face is therefore 5x dimmer than its trailing face

21. Saturn’s Moons Hyperion: u Only satellite in the solar system that is not in synchronous orbit u Not spherical u It is the sixteenth moon out and is 286 km in diameter