1. SATURN’S RINGS Beatriz Frisón Máster en Astrofísica

2. OBSERVATIONS 1610- Galileo: satellites? 1655 – Christian Hygens: rigid matter disk 1675– Cassini: Cassini division XVIII- Laplace: thin rings 1857- Maxwell: little mass 1895- Keeler y Campbell: velocity

3. 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 10 19 kg ?? Thin gaps & ringlets

4. MAIN RINGS STRUCTURE

5. RADIUSRADIUS/OPTICALALBEDOTHICKNESS SURF. DENSITY ECCENTRICI TY (KM) EQ. RADIUS DEPTH(M)(G/CM2) SATURN EQUATOR60,2681.000 D INNER EDGE66,91.110 D OUTER EDGE74,511.236 C INNER EDGE74,6581.2390.05 - 0.100.12 - 0.3051.4 -5 TITAN RINGLET77,8711.292170.00026 MAXWELL GAP/RINGLET 87,4911.452170.00034 C OUTER EDGE921.5270.120.252-7 B INNER EDGE921.5270.4 - 2.50.4 - 0.65-1020 -100 B OUTER EDGE117,581.9511.8 CASSINI DIVISION0.05 - 0.150.2 - 0.42018 -20 A INNER EDGE122,172.0270.4 - 1.00.4 - 0.610-3030 -40 ENCKE GAP133,5892.216 KEELER GAP136,532.265 A OUTER EDGE136,7752.2690.60.4 - 0.610-3020 -30 F RING CENTER140,182.3260.10.60.0026 G INNER EDGE1702.821.0 X 10-6105 G OUTER EDGE1752.90 E INNER EDGE18131.5 X 10-5107 E OUTER EDGE4838107

6. 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).

7. 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.

8. PHOEBE RING 06/10/2009 – Spitzer i = 27˚ R= 6 -12 x 10 6 km Thickness: 20 D saturn Phoebe inside

9. 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 2004. (Saturn is off to the lower left.)

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

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