SATURN’S RINGS Beatriz Frisón Máster en Astrofísica

OBSERVATIONS Galileo: satellites? 1655 – Christian Hygens: rigid matter disk 1675– Cassini: Cassini division XVIII- Laplace: thin rings Maxwell: little mass Keeler y Campbell: velocity

MAIN CHARACTERISTICS Alphabetic order by discovery date 9 main rings. Total ≈ 140 Dense rings: 7,000 km – 80,000 km (Req) Thickness ≈ 10m – 30,000km Total Mass = 3 x kg ?? Thin gaps & ringlets

MAIN RINGS STRUCTURE

RADIUSRADIUS/OPTICALALBEDOTHICKNESS SURF. DENSITY ECCENTRICI TY (KM) EQ. RADIUS DEPTH(M)(G/CM2) SATURN EQUATOR60, D INNER EDGE66, D OUTER EDGE74, C INNER EDGE74, TITAN RINGLET77, MAXWELL GAP/RINGLET 87, C OUTER EDGE B INNER EDGE B OUTER EDGE117, CASSINI DIVISION A INNER EDGE122, ENCKE GAP133, KEELER GAP136, A OUTER EDGE136, F RING CENTER140, G INNER EDGE X G OUTER EDGE E INNER EDGE X E OUTER EDGE

INNER RINGS From inside to outside: D ring: faint, small. Ringlets C ring: Inner: Colombo Gap, Titan Ringlet Outer: Maxwell Gap, Maxwell Ringlet B ring: brilliant, massive Cassini Division: 2:1 Mimas Huygens Gap: inner border, 2:01 Mimas A ring: Atlas. 7:06 with Jano and Ephimeteo. Encke Gap: Pan inside Keeler Gap: Dapthnis inside Rocke Division F ring: thick, shepherd moons (Prometeus, Pandora).

OUTER RINGS From inside to outside: Janus / Epimetheus ring: faint, 5,000 km G ring: thin, Ring arc at 7:6 Mimas (Aegaeon) Methone Ring arc: 14:15 Mimas Anthe Arc Ring: 10:11 Mimas Palene Arc Ring: 2500 km E Ring: from Mima to Rhea.

PHOEBE RING 06/10/2009 – Spitzer i = 27˚ R= x 10 6 km Thickness: 20 D saturn Phoebe inside

RING WAVES Above: Waves in Saturn's A ring. The bands in the lower left are spiral density waves, and the bands in the upper right are bending waves. This image was taken by the Cassini spacecraft in (Saturn is off to the lower left.)

COMPOSITION 99% ice Tolins Silicates Thin Atmosphere: O 2, H 2, OH

RINGS FORMATION THEORIES Roche: satellite – tidal forzes Nebular material Canup RM theory