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12a. Jupiter

12a. Jupiter. Jupiter data Jupiter seen from the Earth Jupiter rotation & structure Jupiter clouds Jupiter atmospheric motions Jupiter rocky core Jupiter magnetic field. Jupiter Data (Table 12-1). Jupiter Data: Numbers. Diameter: 142,800.km 11.19 ⋅ Earth

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12a. Jupiter

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  1. 12a. Jupiter • Jupiter data • Jupiter seen from the Earth • Jupiter rotation & structure • Jupiter clouds • Jupiter atmospheric motions • Jupiter rocky core • Jupiter magnetic field

  2. Jupiter Data (Table 12-1)

  3. Jupiter Data: Numbers • Diameter: 142,800.km 11.19 ⋅ Earth • Mass: 1.9 ⋅ 1027 kg 317.8 ⋅ Earth • Density: 1.3 ⋅ water0.24 ⋅ Earth • Orbit: 7.8 ⋅ 108 km 5.20 AU • Day: 9h.50m 30s0.41 ⋅ Earth • Year: 11.86 years 11.86 ⋅ Earth

  4. Jupiter Data: Special Features • Jupiter is the closest Jovian planet to the Sun • Jupiter is the largest Jovian planet • Jupiter is ~2.5 . mass of all other planets combined • Jupiter has no solid surface • Jupiter has a colorful & dynamic atmosphere • Great Red Spot, belts & zones… • Jupiter’s interior consists of three layers… • Atmosphere: Liquid molecular hydrogen • Mantle: Liquid metallic hydrogen • Core: “Metal” & “rock” • Jupiter has 4 large & 63 small known moons • Io is the most volcanically active body known

  5. Jupiter As Seen From Earth • The first telescopic observer of Jupiter • Galileo Galilei 1610 • Immediately noticed the four largest moons of Jupiter • Recognized the similarity between them and the planets • More recent telescopic observers • Robert Hooke 1664 • Noticed the Great Red Spot in the southern hemisphere • It has persisted in some form until now • Cassini 1690 • Cloud bands drawn out by Jupiter’s very fast axial rotation • Used these to measure 9h 50m 28s equatorial Jovian day • Discovered Jupiter’s differential axial rotation Rotation • Jupiter rotates fastest at its equator than at its poles

  6. Jupiter is Made of Low-Mass Gases • Jupiter is mostly hydrogen & helium • The numbers • By mass ~ 71% H2 ~ 24% He ~ 5% others • By atoms ~ 91% H2 ~ 8% He ~ 1% others • The evidence • Detected spectra of CH4 (methane) & NH3 (ammonia) • Cold H2 & He are extremely difficult to detect • UV spectra detected in 1960 • Jupiter does have a rocky & metallic core • May have been the “seed” for the rest of Jupiter

  7. Cloud Details in Spacecraft Images • Pioneer 10 & Pioneer 11 fly-bys 1973 & 1974 • First close-up images of Jupiter • Spectacular images of Galilean moons, esp. Io • Voyager 1 & Voyager 2 fly-bys 1979 • Spectacular close-ups of Jovian storm systems • Additional details of most Jovian moons • Galileo atmospheric probe & orbiter 1995 • Probe entered clear area in Jupiter’s clouds • Severely crippled yet operated until 21 Sep. 2003 • Cassini 2000 • The primary mission is to Saturn • Imaged Jupiter during gravity-assist [slingshot] fly-by • Simultaneous observations by Galileo

  8. Patterns In Jupiter’s Clouds

  9. Jupiter Seen From Far & Near Earth-based telescope Voyager 1 spacecraft

  10. Five Historic Views of Jupiter

  11. Jupiter’s Great Red Spot • Solar System champ • Longest lasting storm system Since 1664 • Largest storm system ~ 25,000 mi • Basic characteristics • Imbedded in Jupiter’s southern hemisphere • Much higher than surrounding clouds • Circulates counterclockwise • Characteristic of a high pressure system • Similar to high pressure systems in Earth’s atmosphere • Size varies considerably • From ~ 1 to ~3 times Earth’s diameter • Color varies considerably • From deep red to light pink

  12. Voyager 2: The Great Red Spot

  13. Jupiter & Ganymede: Family Portrait

  14. Three Factors Affect Cloud Motions • InsolationIncoming solar radiation • Jupiter’s orbit is ~ 5.2 AU from the Sun • ~ 3.7% as much energy per m2 as Earth • Jupiter’s albedo is 0.44 compared to Earth’s 0.39 • Effectively reduces solar energy to ~ 3.3% of Earth • Sunlight is absorbed by Jupiter’s atmosphere • Jupiter’s internal heat • Jupiter emits ~ 2x as much energy as from sunlight • Old heat from Jupiter’s formation • New heat from helium condensation • Differential axial rotation • Multiple convection cells in Jupiter’s atmosphere • Drawn out into bands parallel to Jupiter’s equator • Adjacent bands move in opposite directions Zonal winds

  15. Spectroscopy of Jupiter’s Atmosphere • Three primary cloud layers • Upper layer ~ 20 km below Tmin • Ammonia (NH3) ice crystals • Middle layer ~ 40 km below Tmin • Ammonium hydrosulfide (NH4SH) ice crystals • Lower layer ~ 60 km below Tmin • Water (H2O) ice crystals • Major cloud features • Belts & zones • Belts are bands of falling air Relatively low & warm • Zones are bands of rising air Relatively high & cool • Brown & white ovals • White ovals lie relatively high in Jupiter’s atmosphere • Smaller versions of the Great Red Spot • Brown ovals lie relatively low in Jupiter’s atmosphere

  16. Jupiter’s Upper Atmosphere Structure

  17. Jupiter’s (Low) Belts & (High) Zones

  18. Jupiter’s Distinctive Cloud Colors • Mostly “Earth tones” • Yellow, brown, pink, red… • Colors vary over time & space • Source of colors • All three cloud layer chemicals are white if pure • Spectroscopy reveals no substantial impurities • Jupiter’s moon Io is extremely active volcanically • Io has abundant sulfur compounds • Io has the same colors as Jupiter’s clouds • Io spews matter into space near Jupiter • Jupiter’s cloud colors may come from Io’s eruptions

  19. Jupiter’s Deep Atmosphere: S-L 9 • Comet Shoemaker-Levy 916-22 July 1994 • 23 visible fragments entered Jupiter’s atmosphere • All less than ~ 1 km in diameter • Entry speed of ~ 60 km ⋅ sec–1 ~ 130,000 mph • Satellites orbit Earth at ~ 8 km ⋅ sec–1 • Largest fragment energy equivalent of 6 ⋅ 108megatons • 10,000°C fireballs rose 3,000 km above the clouds • Hopes for eruptions of deep atmospheric layers • Confounded by uncertainties about comet’s composition

  20. S-L9: The String of Pearls Comet

  21. Comet Shoemaker-Levy 9 Hits Jupiter

  22. Jupiter’s Deep Atmosphere: Galileo • Galileo atmospheric probe 7 December 1995 • Only spacecraft to enter Jupiter’s atmosphere • Entry speed of ~ 49 km . sec–1 ~ 106,000 mph • Decelerated to ~ 40 km . hr–1 in 3 min. ~ 25 mph • Descended by parachute for ~ 1 hour • Reached ~ – 200 km & + 24 x Earth’s air pressure

  23. Jupiter’s Atmosphere Findings • Relatively rare but extremely powerful lightning • Nearly constant winds of ~ 650 km ⋅ hr–1 • Much faster than solar-driven high altitude winds • This wind energy must come from Jupiter’s interior • Cloud layer measurements • Galileo Probe’s bad luck ⇒ Entered a clear spot • Traces of NH3 & NH4SH clouds but no H2O clouds • Atmospheric gases • Virtually identical to the Sun • Only ½ expected amount of atmospheric H2O vapor

  24. The Galileo Probe Timeline Probe video

  25. Oblate Shape Means a Rocky Core • Distinctly larger equatorial than polar diameter • ~ 6.5 % difference for Jupiter • ~ 0.34% difference for Earth • Axial rotation spins equatorial material away • Centrifugal effect • Planetary core mass modifies centrifugal effect • Metallic & rocky inner core • Estimated to be ~ 2.6% of Jupiter’s mass • Only ~ 8 x Earth’s mass yet ~ 86% Earth’s diameter • Liquid “ices” outer core • Primarily water (H2O), methane (CH4) & ammonia (NH3) • Estimated to be ~ 3,000 km thick

  26. Jupiter’s Four-Layer Internal Structure Jupiter's Interior

  27. Metallic Hydrogen & Magnetosphere • Radio observations of Jupiter 1950’s • Evidence of electric currents • Different types of radio emissions • Thermal emissions Blackbody radiation • Non-thermal emissions • Wavelengths of a few meters Decametric radiation • Wavelengths of a few tenths of a meter Decimetric radiation • Jupiter’s magnetic field is ~ 14 x Earth’s magnetic field • Possible causes • H2 is a liquid metal above 1.4 . 106 atmospheres • Pressure is reached ~ 7,000 km below Jupiter’s clouds • The “gas giant” Jupiter is mostly liquid metallic hydrogen

  28. Jupiter’s Immense Magnetosphere • Spacecraft measurements • Pioneer & Voyager • Magnetosphere is ~ 3.0 . 107 km in diameter • ~ 210 times Jupiter’s diameter as seen from Earth • ~ 2.5 times the Moon’s diameter as seen from Earth • ~ 6.3 times the Moon’s area as seen from Earth • Magnetosphere extends beyond the orbit of Saturn • Jupiter’s magnetotail is ~ 6 AU long • Emissions variations repeat every 9h 55m 28s • Assumed to be the core axial rotation rate of Jupiter • Galileo • Suffered extensive radiation damage orbiting Jupiter • Basic characteristics • Jupiter’s magnetosphere is filled with plasma • Solar wind gusts alter Jupiter’s magnetosphere • Magnetosphere’s size varies by a factor of 2

  29. A schematic view A radio view Jupiter’s Magnetosphere

  30. Juno: Jupiter’s Newest Spacecraft • Basic details • Launched 5 August 2011 • Six-year planned mission • 5 years from Earth to Jupiter Arrives 5 July 2016 • 1 year science mission • Science objectives • Determine O2 abundance in Jupiter’s atmosphere • Better estimate of Jupiter’s core mass • Precisely map Jupiter’s interior mass distribution • Precisely map Jupiter’s magnetic field • Map variations in atmospheric properties • Jupiter’s polar magnetosphere & aurorae • Measure general relativistic orbital frame-dragging

  31. Juno’s Scientific Instruments • Microwave radiometer • Jovian Infrared AuroralMapper • Magnetometer • Gravity Science • Jovian Auroral Distribution Experiment • Jovian Energetic Particle Detector Instrument • Radio and Plasma Wave Sensor • Ultraviolet Imaging Spectrograph • JunoCam

  32. Juno’s Route to Jupiter http://upload.wikimedia.org/wikipedia/commons/b/ba/Juno%27s_interplanetary_trajectory.jpg

  33. The Juno Spacecraft at Jupiter http://upload.wikimedia.org/wikipedia/commons/b/b3/Juno_Mission_to_Jupiter_%282010_Artist%27s_Concept%29.jpg

  34. The Juno Spacecraft 33 Orbits http://upload.wikimedia.org/wikipedia/en/3/39/Juno_trajectory_through_radiation_belts.png

  35. Juno’s Mission at Jupiter • Polar orbit • Highly elliptical • Spend minimum time in Jupiter’s radiation belts • Planned 33 orbits • Juno de-orbited to crash into Jupiter • Possibility of an extended mission • Mainly an issue of fuel for orientation thrusters

  36. Jupiter data ~ 11.2 times Earth’s diameter ~ 318 times Earth’s mass ~ 2.5 times the mass of all planets Jupiter as seen from Earth Distinctly oblate shape Distinctive cloud bands & storms Four extremely obvious moons Distinctive features Axial rotation period of ~ 10 hours Solar System’s most colorful clouds Composed mostly of H & He Almost same composition as the Sun Jupiter’s cloud details Prominent cloud belts & zones Prominent spots Great Red Spot White & brown ovals Jupiter’s deeper atmosphere Comet Shoemaker-Levy 9 23 fragments < 1 km in diameter Galileo Probe spacecraft 1 tiny spacecraft for ~ 1 hour Jupiter’s four-layer internal structure Ordinary gaseous hydrogen & helium Helium & liquid metallic hydrogen Liquid “ices” (H2O, CH4 & NH3) Rocky & metallic core Jupiter’s magnetosphere Magnetic field strength ~ 14 x Earth’s Circulating liquid metallic hydrogen Very fast axial rotation Magnetic field size Width of ~ 210 x Jupiter’s diameter Length of ~ 6 AU (past Saturn’s orbit) Deflates quickly due to solar wind Important Concepts: Jupiter

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