Rings of Saturn
icy particles in orbit around Saturn
- Doppler shifts (Keeler) show they follow Kepler’s laws
- 3100 nm absorption indicates ice, as for Galilean satellites
Within the Roche limit
- either a failed satellite or interloper torn apart
sub-mm to m sized particles
- scattering of visible and radio waves
- radio transmission experiment of Voyager
Intricate structure
- Gaps in rings caused by gravitational interactions
- Example: Cassini division
- between bright “A” and “B” rings
- period would be 11.3 hr. cf. Mimas’ 22.6 hr. period
- exact 2:1 resonance
- any particles orbiting in gap pulled away, like Io is by Europa