1. The Outer Planets

2. Cosmic Abundance of Elements HydrogenH11,000,000 HeliumHe280,000 CarbonC6363 NitrogenN7112 OxygenO8851 NeonNe10117 SodiumNa112 MagnesiumMg1232 AluminumAl133 SiliconSi1445 SulfurS16 ArgonAr181 CalciumCa202 IronFe2636 NickelNi282

3. Major Constituents GasFormulaJupiterSaturn HydrogenH2H2 86%92% HeliumHe14%7% MethaneCH 4 0.2% AmmoniaNH 3 0.02% WaterH2OH2O~0.2% (?)~0.4% (?)

4. Interiors: Big H 2 Atmospheres

5. Jupiter vs Saturn

6. Jupiter’s Ammonia Clouds: Belts: Dark bands Zones: Bright bands Great Red Spot White Ovals The GRS has lived at least 300 yrs. Ovals have been seen to survive tens of years

7. Jupiter’s clouds result from convection. 1)Hot air expands. 2)Lighter than the rest of the air, it rises. 3)As it rises, it cools and condenses forming clouds. 4)When it is cooler than the ambient air, it sinks.

8. Great Red Spot

9. Saturn’s Clouds

10. Uranus Absorption of sunlight at red wavelengths by methane renders the planet blue.

11. Neptune Neptune emits more energy from its interior than does Uranus. This energy drives weather. The colder temperatures cause methane to condense in the upper atmosphere – these are the clouds that we see.

12. Jupiter’s Rings Silicate dust, 10,000 times more transparent than window glass.

13. Moons A typical, heavily cratered, terrain. Saturn’s moon, Tethys Their densities tell us that they are 1/2 rock & 1/2 ice.

14. Jupiter’s Moons

15. Europa Few craters A terrain containing elements that were recently dislodged can be seen to neatly fit together if rotated and translated in position.

16. Io Images\iovol_vgr.gif Io

17. What fuels Io? Each time Ganymede orbits once, Europa orbits twice, and Io orbits 4 times.

18. Plumes fountain 500 km above the Surface

19. Io’s surface is almost devoid of craters, for it is being repaved at a rapid rate. The glow of warm lava. A pool of lava (black) covered with sulfur deposits (orange). This is called Tupan Patera after the Brazilian thunder god. Images taken from the Galileo spacecraft.

20. Io is hot Lava flows on Io exceed 1500 K in temperature. Lavas this hot are not sulfur (which would evaporate immediately). This is hotter than present lavas on Earth (1300-1450 K). Instead these lavas are likely ultramafic (rich in Mg and Fe), similar to the lavas that occurred on early Earth. Present hypothesis, a ~100 km thick crust floats on top of a worldwide ocean of magma 800 km deep.

21. Triton Neptune’s Largest Moon: Triton On Triton the main component of the atmosphere, nitrogen, exits in vapor pressure equilibrium. That is, it exists as an ice on the surface and as vapor in the atmosphere, in the same way that water exists as liquid and ice on Earth’s surface and as a gas in the atmosphere. The amount of gas depends on the temperature. Less exists at cooler temperatures. This is seen on Earth with the condensation of water at dew point. Atmosphere: 1.6x10-7 bar 38K Nitrogen

22. Summary Giant planets are large gas planets with nearly solar elemental abundances. They have small ice-rock cores. Their moons are ½ rock and ½ ice. Most moons display heavily cratered terrains. Io, Europa, Triton and Titan are exceptions. All jovian planets sport rings of differing thicknesses, compositions & character. Titan supports an atmosphere second only to Venus’ (considering bodies with proper surfaces). It is rich with organics, and its origin is unknown. The Cassini mission to the saturnian system is in route and functioning well.

23. Titan: a moon with an atmosphere

24. Saturn’s largest moon compared to Jupiter’s largest moons Ganymede Size: 4800 Mass: 1.5x10 23 Callisto Size: 5268 Mass: 1.1x10 23 Titan Size:5150 km Mass: 1.3x10 23

25. Observações da alta atmosfera

26. Composition of Titan’s stratosphere Molecule Abundance Molecule Abundance N 2 65-98% CH 4 2-10% H 2 0.2-0.6% CO 6-150 ppm CH 3 D 5-180 ppm C 2 H 6 13-20 ppm C 2 H 2 2-5 ppm C 3 H 8 0.5-4 ppm C 2 H 4 0.09-3 ppm HCN 0.2-2 ppm HC 3 N 80-250 ppb CH 3 C 2 H 4-60 ppb C 4 H 2 1-40 ppb C 2 N 2 5-16 ppb CO 2 1.5-14 ppb Derived from radiative transfer analyses of Voyager, ISO and ground-based data.

27. Oceans? CH 4 C2H6C2H6 C2H2C2H2 haze  + CH 4 -> other hydrocarbons Methane in atmosphere is depleted in10 7 years. Either methane is supplied or we are witnessing Titan at a particular moment in its history. Oceans containing methane explain the near saturated tropospheric conditions, provide a source for methane, and don’t require a penchant for being lucky. Flasar et al. Science 221, 55 Lunine et al. Science 222, 1229 Ocean (CH 4, C 2 H 6, N 2 ) hνhν 

28. Production Rate SpeciesFluxDepth*Phase C2H6C2H6C2H6C2H6 5.8x10 9 cm -2 s -1 600 m liquid C2H2C2H2C2H2C2H2 1.2x10 9 cm -2 s -1 100 m solid C3H8C3H8C3H8C3H8 1.4x10 8 cm -2 s -1 20 m liquid HCN 2.0x10 8 cm -2 s -1 20 m solid Haze 1.5x10 -14 g cm -2 s -1 60 m solid Taken from Lunine et al. 1989. Based on Yung et al. 1984, Raulin (1984) * Depth assuming global coverage & 4.5 Gyr of production

29. Expected Surface Scenario Sagan & Dermott 1982

31. Titan’s Surface HST images Peter Smith et al. U. of Arizona

34. Testing Cassini (Jet Propulsion Laboratory, California) We can see the main antenna. All the instruments (e.g. the cameras) are covered.

35. Huygens Probe, European Space Agency We can see the shield that protects the instruments against the heat of entry into the atmosphere.

36. In 2005, the desent of Huygen’s into Titan’s atmosphere. At 170 km altitude, Huygens releases the shield and begins measurements.

37. Cassini-Huygens spacecraft, on a Titan IV rocket, waiting for takeoff. 15 October 1997

38. A perfect takeoff that saved fuel.

39. ISS Images

40. Huygens DIRS Descent Movie  View of Landing Site Ice Mountains Landing Site

41. Huygen’s DISR Images PI: Marty Tomasko University of Arizona Foreground stones are 6 inches

42. DISR More DISR Images.

43. Washes flow downhill Tomasko et al. Nature 438, 765

44. Huygens aterrizou ~30km ao sul das dunas  Imagem do Cassini Radar (no modulo orbital) Sitio de aterrissagem Larry Soderblom

55. Tropical Dunes

56. Washes in Xanadu

57. Cassini RADAR

58. Lakes

59. Seas

60. Titan 60 o N latitude line ~ 1 m of surface CH 4 ~ 4 m of atmospheric CH 4 Cassini Radar 2.7 km of water on the surface 2.5 cm of atmospheric water Earth

61. Sotin et al. Nature 435, 786 (2005) Cryovolcanism

62. A Mystery about Titan Where is the ethane (C 2 H 6 )? N 2, CH 4 Atmosphere C2H6C2H6

63. A Mystery about Titan Where is the ethane (C 2 H 6 )? N 2, CH 4 Atmosphere C2H6C2H6

64. Titan’s Two Kinds of Clouds 40 20 Ethane (C 2 H 6 ) Methane (CH 4 )

66. Summary Titan, Saturn’s largest moon, has an atmosphere10 times thicker than Earth’s. This atmosphere is mainly of N 2 and contains a lot of organic material. Titan sports a methane cycle, with clouds, rain & seas. Methane is the source of organic material in Titan’s atmosphere and on its surface. It’s not entirely clear how and when Titan outgassed its methane, but the dearth of ethane suggests that it happened within 1 billion years. The complexity of the organic chemistry is unclear.

67. Um Balão para Titã