Vital Statistics for Saturn's Rings and Inner Satellites

Rings of Saturn

Feature	Boundaries (km)		Optical Depth	Footnotes and comments
	Inner	Outer
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.
Methane 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

1. Murray, C.D. and S.F. Dermott, "Solar System Dynamics", Cambridge University Press, 1999.
2. 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
3. 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.
4. Porco, C.C., on behalf of the Cassini Imaging Team, 2008. R/2006 S 5 and R/2007 S 1. IAU Circ. 8970.
5. Verbiscer, A.J., Skrutskie, M.F., and D.P. Hamilton, "Saturn’s largest ring", Nature Ltrs, 461, 22 October 2009.
6. Tiscareno, M.S., (private communication), estimated values based on semimajor axis of Daphnis and nominal gap width of 35km.

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

1. JPL Horizons: Mean orbital elements referred to the local Laplace planes, Epoch 2000 Jan. 1.50.
2. JPL Horizons: Mean orbital elements referred to the Saturn equator, Epoch 2004 Jan. 1.00.
3. JPL Horizons: Mean orbital elementsred referred to the ecliptic,Epoch 2000 Jan. 1.00.
4. 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.
5. Physical parameters from Murray, C.D., and S.F. Dermott, "Solar System Dynamics", Cambridge University Press, 1999.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
11. 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.

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