Vital Statistics for Saturn’s Rings and Inner Satellites

Rings of Saturn

Feature Inner Boundary Outer Boundary Optical Depth Footnotes and comments
  (km) (km)    
D Ring 66,900 74,658 10-5 1. Contains narrow ringlets at 67,580 and 71,710 km.
C Ring 74,658 91,975 0.05 to 0.35 1. Isolated “plateaus” among a surrounding, fainter ring.
Titan Ringlet 77,871 77,896   1. A narrow, eccentric ringlet inside a gap in the C Ring.
Maxwell Ringlet 87,491 87,555   1. A narrow, eccentric ringlet inside a gap in the C Ring.
1.470 Rs Ringlet 88,716 88,732   1. A narrow, eccentric ringlet inside a gap in the C Ring.
1.495 Rs Ringlet 90,171 90,232   1. A narrow, eccentric ringlet inside a gap in the C Ring.
B Ring 91,975 117,507 0.4 to 2.5 1. Contains fine structure on all scales. The most opaque of Saturn’s rings.
Cassini Division 117,507 122,340 0 to 0.1 1. The prominent gap between the A and B Rings. It contains several features of low optical depth.
Huygens Ringlet 117,825 118,185   1. A narrow, eccentric ringlet near the inner edge of the Cassini Division.
A Ring 122,340 136,780 0.4 to 1.0 1. A fairly uniform ring with many density and bending waves near its outer edge.
Encke Gap 133,410 133,740 ~0 1. A gap in the A Ring maintained by the embedded moon Pan. One or more faint ringlets are also present.
Keeler Gap 136,487 136,522 ~0 6. A narrow gap in the outer A Ring maintained by the embedded moon Daphnis.
F Ring 139,826 140,612   1. A complex, narrow, eccentric, inclined ring with a denser core at a=140,219 km demonstrating a wide variety of quasi-stable and ephemeral structure.
Janus/Epimetheus Ring 149,000 154,000   2. A narrow, very faint ring in the region occuppied by Janus and Epimetheus.
G Ring 166,000 173,200 10-6 1. A faint, isolated dust ring.
E Ring 180,000 480,000 10-6 1. A broad, faint dust ring encompassing the orbits of Mimas through Dione. Densest near the orbit of Enceladus. Up to ~ 30,000 km thick.
Methone Ring ~194,440     3. A narrow, very faint ring in the the region occuppied by Methone.
Anthe Ring ~197,655     4. A narrow, very faint ring in the orbit of Anthe.
Pallene Ring ~212,000     2. A narrow, very faint ring in the region occuppied by Pallene.
Phoebe Ring 7,722,240 12,488,310 ~2x10-8 5. A broad, faint ring in the orbit of Phoebe with a vertical extent of 2,413,200 km.

Sources

  • Murray, C.D. and S.F. Dermott, “Solar System Dynamics”, Cambridge University Press, 1999.
  • Porco, C.C., and the Cassini Imaging Team, 2006. Rings of Saturn (R/2006 S 1, R/2006 S 2, R/2006 S 3, R/2006 S 4). IAU Circ. 8759
  • Roussos, E., Jones, G.H., Krupp, N., Paranicas, C., Mitchell, D.G., Krimigis, S.M., Woch, J., Lagg, A., Khurana, K., 2008. Energetic electron signatures of Saturn’s smaller moons: Evidence of an arc of material at Methone. Icarus 193, 455-464.
  • Porco, C.C., on behalf of the Cassini Imaging Team, 2008. R/2006 S 5 and R/2007 S 1. IAU Circular 8970.
  • Verbiscer, A.J., Skrutskie, M.F., and D.P. Hamilton, “Saturn’s largest ring”, Nature Letters, 461, 22 October 2009.
  • Tiscareno, M.S., (private communication), estimated values based on semimajor axis of Daphnis and nominal gap width of 35 km.

Regular Satellites of Saturn

Name Semimajor Axis Period Eccentricity Inclination Mean Diameter Mass Footnotes and comments
  (km) (days)   (deg) (km) (kg)  
Pan 133,580 0.575 0.00001 0.0001 20 4.5x1015 6,7.
Daphnis 136,505 0.594 0.00003 0.0036   6.8x1013 6,7.
Atlas 137,670 0.602 0.0012 0.003 16 6.6x1015 2,9.
Prometheus 139,380 0.613 0.0022 0.008 100 1.594x1017 2,9. Prometheus and Pandora interact to produce chaotic orbit changes.
Pandora 141,720 0.629 0.0042 0.05 84 1.37x1017 2,9. Prometheus and Pandora interact to produce chaotic orbit changes.
Epimetheus 151,410 0.694 0.0098 0.351 118 5.264x1017 2,9. Janus and Epimetheus are ‘coorbital’ and undergo orbit changes at approximately 4 year intervals.
Janus 151,460 0.695 0.0068 0.163 178 1.897x1018 2,9. Janus and Epimetheus are ‘coorbital’ and undergo orbit changes at approximately 4 year intervals.
Aegaeon 167,494 0.808 0.00043 0.0007 <1   11. Embedded in the G Ring.
Mimas 185,539 0.942 0.0196 1.574 397 3.7493x1019 1,8.
Methone 194,440 1.010 0.0001 1.007 3   2,10.
Anthe 197,655 1.037 0.0012 0.0017 2   4.
Pallene 212,280 1.154 0.004 0.181 4   2,10.
Enceladus 238,037 1.37 0.0047 0.009 504 1.08022x1020 1,8.
Tethys 294,672 1.888 0.0001 1.091 1066 6.17449x1020 1,8.
Telesto 294,710 1.888 0.0002 1.18 22   2,5. Leading coorbital of Tethys.
Calypso 294,710 1.888 0.0005 1.499 20   2,5. Trailing coorbital of Tethys.
Polydeuces 377,200 2.737 0.0192 0.177 4   2,5. Trailing coorbital of Dione.
Dione 377,415 2.737 0.0022 0.028 1123 1.095452x1021 1,8.
Helene 377,420 2.737 0.0071 0.213 32   2,5.Leading coorbital of Dione.
Rhea 527,068 4.518 0.001 0.333 1529 2.306518x1021 1,8.
Titan 1,221,865 15.95 0.0288 0.312 5151 1.34520029x1023 1,8.
Hyperion 1,500,934 21.28 0.0232 0.615 266 5.584x1018 1,8.
Iapetus 3,560,851 79.33 0.0293 8.313 1471 1.805635x1021 1,8.
Phoebe 12,947,913 550.3 0.1634 175.243 213 8.292x1018 1,8.

Notes

  • JPL Horizons: Mean orbital elements referred to the local Laplace planes, Epoch 2000 Jan. 1.50.
  • JPL Horizons: Mean orbital elements referred to the Saturn equator, Epoch 2004 Jan. 1.00.
  • JPL Horizons: Mean orbital elementsred referred to the ecliptic,Epoch 2000 Jan. 1.00.
  • Cooper, N.J., C.D. Murray, M.W. Evans, K. Beurle, R.A. Jacobson, and C.C. Porco, “Astrometry and dynamics of Anthe (S/2007 S 4), a new satellite of Saturn”, Icarus 195, 765-777, 2008.
  • Physical parameters from Murray, C.D., and S.F. Dermott, “Solar System Dynamics”, Cambridge University Press, 1999.
  • Orbital elememts from Jacobson, R.A., J. Spitale, C. C. Porco, K. Beurle, N. J. Cooper, M.W.Evans, and C. D. Murray, Revised Orbits Of Saturn’s Small Inner Satellites, Astronomical Journal, 135:261-263, 2008.
  • Masses from Weiss, J.W., C.C. Porco, and M.S. Tiscareno, Ring Edge Waves And The Masses Of Nearby Satellites, Astronomical Journal, 138:272-286, 2009.
  • Physical parameters from Jacobson, R.A., P.G. Antreasian, J.J. Bordi, K.E. Criddle, R. Ionasescu, J.B. Jones, R.A. Mackenzie, M.C. Meek, D. Parcher, F.J. Pelletier, W.M. Owen, Jr., D.C. Roth, I.M. Roundhill, and J.R. Stauch, The Gravity Field Of The Saturnian System From Satellite Observations And Spacecraft Tracking Data, Astronomical Journal, 132:2520-2526, 2006.
  • Masses from Jacobson, R.A., J. Spitale, C. C. Porco, K. Beurle, N. J. Cooper, M.W.Evans, and C. D. Murray, Revised Orbits Of Saturn’s Small Inner Satellites, Astronomical Journal, 135:261-263, 2008. 10 Spitale 2006.
  • Porco, C. C., P. C. Thomas, J. W. Weiss, and D. C. Richardson 2007. Saturn’s small inner satellites: Clues to their origins. Science 318, 1602-1607.
  • Hedman, M. M., N.J. Cooper, C.D. Murray, K. Beurle, M.W. Evans, M.S. Tiscareno, and J. A. Burns, Aegaeon (Saturn LIII), a G-ring object, eprint arXiv:0911.0171 [astro-ph.EP], 2009.