ASTR 1010 1st EditionLecture 21Outline of Last Lecture I. JupiterA. AtmosphereB. PropertiesC. Magnetic PropertiesD. Internal StructureE. SatellitesOutline of Current LectureI. SaturnA. AtmosphereB. PropertiesC. Magnetic PropertiesD. Internal StructureE. SatellitesII. UranusIII. NeptuneIV. PlutoCurrent LectureI. JupiterA. Atmosphere- H, He, and Methane (Ammonia not detected)- Horizontal bands in the atmosphere (low contrast due to absence of Ammonia)- Rotational period (Differential Rotation, fluid planet)a. 10 hrs. 16 min.b. 10 hrs. 40 min.- Radiates more energy than it receives from the sun due to slow contraction of planet.- Would float in water. Density = .75 D (Earth)B. Properties- Orbital Period: 29.4 years- Tilt of Axis of Rotation: 26.7 degrees- Mass: 95 M(Earth)- Radius: 9.45 R(Earth)- Extensive Ring Systema. Cassini Divisionb. Braided Ring – Magnetic Influencec. Shepard SatellitesC. Magnetic Properties- Mag. Field (Saturn) = 0.67 x Mag field of Earth- Tilt of Mag Axis: 9.6 degrees- Radiation belts are depleted due to ringsD. Internal Structure- Core - Metallic Hydrogen- Molecular Hydrogen Mush - Hydrogen-Helium atmosphereE. Galilean Satellites- Titan a. Largest moon of Saturnb. Nitrogen-rich atmospherec. Ionosphere- Mimas: Has large crater on surface near the size necessary to disrupt thismoon- Iapetus: Two hemisphere have extremely different albedos – one is highlyreflective, the other is covered with soot-like material.- Tethys and Dione: Cratered, cracked surface with evidence of some Maria, icy flooding activity- Enceladus: Bright/shiny surface; likely has water ice volcanoes on its surface.II. Uranus- Mass: 14.5 M(Earth)- Rotational Period: 0.72 days- Axial tilt: 98 degrees- Magnetic field: .74 M(Earth)- Tilt of Mag. Axis: 58.6 degrees (Perhaps reversing)- Atmosphere: H, He, Methanea. No internal heat sourceb. High velocity (200-500Km/hr)- Rings: Nine thin rings – Shepard moons, all in Equatorial plane- Satellites (17)a. Oberon & Titania: Heavily cratered, dirty/icy surfaceb. Umbriel: Darkest, one bright spot (unexplained)c. Ariel: Resurfacing/Cracks due to crateringd. Miranda: Ridges/valleys; faults, torturous geological features – disrupted due to internal/external effectsIII. Neptune- Mass: 17 M(Earth)- Rotational Period: 0.67 days- Axial tilt: 29.6 degrees- Magnetic field: .43 M(Earth)- Tilt of Mag. Axis: 46 degrees (Perhaps reversing)- Atmosphere: H, He, Methanea. Slightly warmer than Uranus, internal heat sourceb. Several large storms – “Great dark spot”High velocity (200-500Km/hr)- Rings: five thin rings – predict the existence of Shepard moons - Satellites (8) No moons in roughly circular, prograde orbits (unlike any other planet)a. Triton: Retrograde orbit/20 degrees, tenuous Nitrogen atmosphere, ice surface w/ N-Frost (Pink), lack of cratering-surface activity; Large geysersof Nitrogen erupting.b. Nereid: Prograde, highly elliptical orbitc. Unusual orbits: Triton is deteriorating and will be disrupted in 100,000,000yearsIV. Pluto- Mass: 0.0021 M(Earth)- Rotational Period: 6.387 days- Axial tilt: 118 degrees- Orbit: Tilted 17 degrees, most elliptical- Satellites (1) -
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