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Saturn's Satellites
Saturn has 18 named satellites plus 13 recently discovered and as yet
unnamed ones:
- Of those moons for which rotation rates are known, all but Phoebe and
Hyperion rotate synchronously.
- The three pairs Mimas-Tethys, Enceladus-Dione and Titan-Hyperion interact
gravitationally in such a way as to maintain stable relationships between
their orbits: the period of Mimas' orbit is exactly half that of Tethys,
they are thus said to be in a 1:2 resonance; Enceladus-Dione are also 1:2;
Titan-Hyperion are in a 3:4 resonance.
- In addition to the 18 named satellites, a dozen more have been reported
and given provisional designations but not yet named.
Distance Radius Mass
Satellite (000 km) (km) (kg) Discoverer Date
--------- -------- ------ ------- ---------- -----
Pan 134 10 ? Showalter 1990
Atlas 138 14 ? Terrile 1980
Prometheus 139 46 2.70e17 Collins 1980
Pandora 142 46 2.20e17 Collins 1980
Epimetheus 151 57 5.60e17 Walker 1980
Janus 151 89 2.01e18 Dollfus 1966
Mimas 186 196 3.80e19 Herschel 1789
Enceladus 238 260 8.40e19 Herschel 1789
Tethys 295 530 7.55e20 Cassini 1684
Telesto 295 15 ? Reitsema 1980
Calypso 295 13 ? Pascu 1980
Dione 377 560 1.05e21 Cassini 1684
Helene 377 16 ? Laques 1980
Rhea 527 765 2.49e21 Cassini 1672
Titan 1222 2575 1.35e23 Huygens 1655
Hyperion 1481 143 1.77e19 Bond 1848
Iapetus 3561 730 1.88e21 Cassini 1671
Phoebe 12952 110 4.00e18 Pickering 1898
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