GEOL 3045: Planetary Geology Lysa Chizmadia Saturns Satellites Lysa Chizmadia Saturns Satellites Introduction At least 60 moons Classification of Moons: A-ring Moonlets Ring Shepherds Co-orbitals Inner Large Moons Alkyonides Trojans Outer Large Moons Irregular Moons Inuit Group Norse Group Gallic Group At least 60 moons Classification of Moons: A-ring Moonlets Ring Shepherds Co-orbitals Inner Large Moons Alkyonides Trojans Outer Large Moons Irregular Moons Inuit Group Norse Group Gallic Group Image from:Image from:profile.cfmprofile.cfm?Object=Saturn&Display=Moons A-ring Moonlets 4 discovered in 2006 by Cassini 8 more discovered in 2007 Tiny moons inside the A-ring Diameters: 0.06 to 0.14 km Probably formed due to shattering of inner satellite during impact Discovered by propeller- shaped disturbances in ring 4 discovered in 2006 by Cassini 8 more discovered in 2007 Tiny moons inside the A-ring Diameters: 0.06 to 0.14 km Probably formed due to shattering of inner satellite during impact Discovered by propeller- shaped disturbances in ring Image from:Photo Credit: NASA Ring Shepherds Orbit within or just outside rings Sculpt the rings Giving them sharp edges & gaps 5 named & 3 unconfirmed Pan Daphnis Atlas Prometheus Pandora S/2004 S3, S/2004 S4, S/2004 S6 Orbit within or just outside rings Sculpt the rings Giving them sharp edges & gaps 5 named & 3 unconfirmed Pan Daphnis Atlas Prometheus Pandora S/2004 S3, S/2004 S4, S/2004 S6 Image from:Prometheus (left) & Pandora (right) in Saturns F-ring Image from:http://en.wikipedia.org/wiki/Pan_%28moon%29 Pan in Encke Division Ripples caused by Daphnis Image from:wiki/Daphnis_%28moon%29 Co-orbitals Epimetheus & Janus Orbit differs by only 50 km Inner orbits are faster so must approach each other When inner moon catches outer moon, gravitational attraction boosts inners momentum, increasing orbit Opposite happens to outer moon Thus, they trade places when they pass each other Epimetheus & Janus Orbit differs by only 50 km Inner orbits are faster so must approach each other When inner moon catches outer moon, gravitational attraction boosts inners momentum, increasing orbit Opposite happens to outer moon Thus, they trade places when they pass each other Images from:Epimetheus_%28moon%29 Image from:Janus_%28moon%29 Epimetheus Janus Inner Large Moons Mimas (Herschel crater) Methone Anthe Pallene Enceladus * Tethys Telesto (L4) Calypso (L5) Dione (ice cliffs) Helene (L4) Polydeuces (L5) Mimas (Herschel crater) Methone Anthe Pallene Enceladus * Tethys Telesto (L4) Calypso (L5) Dione (ice cliffs) Helene (L4) Polydeuces (L5)Mimas Dione Enceladus Ice ridges & Cryovolcanism Images from: Outer Large Moons Rhea Homogeneous interior 2 adjacent large craters Possible ring system Titan * Hyperion Chaotic rotation Sponge-like texture Iapetus 2 tone coloration High inclination Equitorial ridge Rhea Homogeneous interior 2 adjacent large craters Possible ring system Titan * Hyperion Chaotic rotation Sponge-like texture Iapetus 2 tone coloration High inclination Equitorial ridge Rhea Image from:Image from:Hyperion Images from:Iapetus Titan Only moon w/ dense atm Pressure: 1.6 bars 98.4% N 2, 1.6% CH 3 & H-Cs CH 3 must be produced Not from comets b/c CO Not from nebula b/c He, Ne Only body with liquid on surface Other than Earth Liquid CH 3 lakes Diameter: 5150 km Mercury: 4879 km Moon: 3474 km Only moon w/ dense atm Pressure: 1.6 bars 98.4% N 2, 1.6% CH 3 & H-Cs CH 3 must be produced Not from comets b/c CO Not from nebula b/c He, Ne Only body with liquid on surface Other than Earth Liquid CH 3 lakes Diameter: 5150 km Mercury: 4879 km Moon: 3474 km Images from: Irregular Moons 3 main groups Inuit Group Norse Group Gallic Group 3 main groups Inuit Group Norse Group Gallic Group Images from:Pheobe Inuit Group Prograde irregular satellites Semi-major axes: x 10 6 km Inclinations: degrees Eccentricities: Spectral homogeneity Similar to Gallic Group Break up of single object 5 members: Kiviuq Ijiiraq Paaliaq Siarnap Tarqeq Prograde irregular satellites Semi-major axes: x 10 6 km Inclinations: degrees Eccentricities: Spectral homogeneity Similar to Gallic Group Break up of single object 5 members: Kiviuq Ijiiraq Paaliaq Siarnap Tarqeq Image from: Norse Group Retrograde irregular satellites Semi-major axes: x 10 6 km Inclinations: degrees Eccentricities: Composed of > 4 subgroups two i=174 subgroups Skathi subgroup Narvi subgroup Retrograde irregular satellites Semi-major axes: x 10 6 km Inclinations: degrees Eccentricities: Composed of > 4 subgroups two i=174 subgroups Skathi subgroup Narvi subgroup Image from: Gallic Group Prograde irregular satellites Semi-major axes: x 10 6 km Inclinations: degrees Eccentricities: ~0.53 Spectral homogeneity Similar to Inuit Group Break up of single object 4 members: Albiorix Bebhionn Erriapus Tarvos Prograde irregular satellites Semi-major axes: x 10 6 km Inclinations: degrees Eccentricities: ~0.53 Spectral homogeneity Similar to Inuit Group Break up of single object 4 members: Albiorix Bebhionn Erriapus Tarvos Image from: Summary At least 60 moons At least 6 groups A-ring moonlets Shepherd moons Co-orbitals Inner large moons Includes Enceladus Outer large moons Includes Titan Irregular Moons Inuit group Norse group Gallic group At least 60 moons At least 6 groups A-ring moonlets Shepherd moons Co-orbitals Inner large moons Includes Enceladus Outer large moons Includes Titan Irregular Moons Inuit group Norse group Gallic group Mimas Herschel Crater Dione Whispy ice ridges Enceladus Ice ridges ~ Europa Cryovolcanism Rhea Homogeneous interior Possible ring system Titan H-C rich atmosphere Liquid HC on surface Hyperion Sponge-like surface texture Iapetus Two-tone surface colors Equatorial ridge Mimas Herschel Crater Dione Whispy ice ridges Enceladus Ice ridges ~ Europa Cryovolcanism Rhea Homogeneous interior Possible ring system Titan H-C rich atmosphere Liquid HC on surface Hyperion Sponge-like surface texture Iapetus Two-tone surface colors Equatorial ridge