NSDF- Natural Satellites Data Files

NSDC/Natural Satellites Data Center

GUIDE FOR THE SATELLITES OF SATURN

The planet Saturn has rings and four families of satellites, orbiting around it:

the rings are easily observable from Earth: the Cassini division between the rings is also visible from Earth and the space probe Voyager put into evidence the large number of rings surrounding Saturn.
the inner satellites: these satellites are orbiting inside the orbit of Mimas, and outside the A ring. Some are orbiting inside the external faint rings seeming to "shepherd" these rings as descibed in the rings table. Because of the closeness of the planet, they are very difficult to observe. Infrared observations are necessary in order to decrease the contrast brightness between the planet and the satellites but, since the rings remain bright, it is easier to wait until the transit of the Earth in the plane of the rings to make observations. At that time, the rings seem to disappear, allowing observations of these faint satellites.
the coorbital satellites: these satellites are orbiting on the same orbit than some main satellites
the main satellites: these satellites are bright, similar to small planets, and easily observable even in a small telescope, except Mimas because of the closeness of Saturn and Hyperion which is the faintest. Their observations are easy to make and they present phenomena due to the closeness and the size of the planet Saturn.
the outer satellites: these satellites are orbiting outside the orbit of Iapetus, the farthest main satellite. They are very faint due to their small sizes and their orbits are neither circular, nor in the equatorial plane of Saturn as the inner and the main satellites (except Iapetus). They are observable as asteroids, independantly of the planet Saturn far from them. Only their faintness is a difficulty for their observation.

The tables below provide the main characteristics of these satellites.

The rings

Rings and inner satellites :	Distance from the beginning of the ring to the centre of Saturn	Size of the ring	Thickness	Albedo
D	67 000 km	7 500 km	?	?
C	74 500 km	17 500 km	?	0,25
Maxwell Division	87 500 km	270 km	-	-
B	92 000 km	25 500 km	0,1 to 1 km	0,65
Cassini Division	117 500 km	4 700 km	?	0,30
A	122 200 km	14 600 km	0,1 to 1 km	0,60
Encke Division	133 570 km	325 km	-	-
Keeler Division	136 530 km	35 km	-	-
satellite Daphnis (S-35)	136 545 km	-	-	-
satellite Pan (S-18)	136 600 km	-	-	-
satellite Atlas (S-15)	137 670 km	-	-	-
satellite Prometheus (S-16)	139 350 km	-	-	-
F ("shepherd" by Prometheus and Pandora)	140 210 km	30 to 500 km	?	?
satellite Pandora (S-17)	141 700 km	-	-	-
Janus (S-10)	151 470 km	-	-	-
Epimetheus (S-11)	151 420 km	-	-	-
G	165 800 km	8 000 km	100 to 1000 km	?
E	180 000 km	300 000 km	1000 km	?

The inner and the coorbital satellites

satellites:	a in km	P in hr, mn, s or in days	eccentricity	inclination on the equator of Saturn	d in km	m_v	ap arcsec	coorbitals: associated satellite
S/1981 S13 - Pan - S 18	133 600	13h 48m	0.0	0.0°	20	?	23"	-
S/2005 S1 - Daphnis - S 35	136 545	14h 15m	0.0	0.0°	7	?	24"	-
S/1980 S28 - Atlas - S 15	137 670	14h 27m	0.002	0.3°	37 x 35 x 27	18	24"	-
S/1980 S27 - Prométhée - S 16	139 350	14h 43m	0.002	0.0°	148 x 100 x 68	15	24"	-
S/1980 S26 - Pandore - S 17	141 700	15h 05m	0.004	0.0°	110 x 88 x 62	15.5	24"	-
S/1980 S3 - Epiméthée - S 11	151 420	16h 39.8m	0.009	0.34°	138 x 110 x 110	15	26"	-
S/1980 S1 - Janus - S 10	151 470	16h 40.3m	0.007	0.14°	194 x 190 x 154	14	26"	-
Mimas	185 540	0.942d	0.019	1°.56	418 x 392.4 x 383	12.9	32"	-
S/2004 S1 - Méthone - S 32	194 000	1.01d	0.0	0.0°	3	?	34"	-
S/2004 S2 - Pallène - S 33	211 000	1.14 d	0.0	0.0°	4	?	35"	-
Encelade	238 200	1.37d	0.005	0.03°	512.6 x 494.6 x 489.2	11.7	41"	-
S/1980 S13 - Télesto - S 13	294 660	1.8878 d	0.001	1.158°	30 x 25 x 15	18	50"	Tethys
S/1980 S25 - Calypso - S 14	294 660	1.8878 d	0.001	1.473°	30 x 16 x 16	18.5	50"	Tethys
Tethys	294 992	1.8878 d	0.0	1.10°	1071.2 x 1056.4 x 1051.6	10.3	51"	-
S/2004 S5 Polydeuces - S 34	377 400	2.74 d	0.0	0.0°	4	?	65"	Dione
S/1980 S6 - Hélène - S 12	377 400	2.74 d	0.0	0.212 °	32	17	65"	Dione
Dione	377 654	2.74 d	0.0022	0.01°	1120	10.4	65"	-

The main satellites

	Mimas S 1	Encelade S 2	Tethys S 3	Dione S 4	Rhea S 5	Titan S 6	Hyperion S 7	Iapetus S 8
semi-major axis in km	185 540	238 200	294 992	377 654	527 367	1 221 803	1 481 100	3 561 850
period of revolution	0.942 422 d	1.370 218 d	1.887 803 d	2 736 916 d	4.517 503 d	15.945 446 d	21.276 673 d	79.330 954 d
eccentricity	0.01905	0.0049	0.0	0.0022	0.0003	0.0291	0.1035	0.0283
inclination on the saturnian equator	1.56 °	0.03 °	1.10 °	0.01°	0.35 °	0.30 °	0.64 °	18.5 °
size in km	418 x 392.4 x 383	512.6 x 494.6 x 489.2	1071.2 x 1056.4 x 1051.6	1120	1528	5150	360 x 280 x 225	1436
m_v	12.9	11.7	10.3	10.4	9.7	8.3	14.19	10.2 to 11.9
ap	32 arcsec	41 arcsec	51 arcsec	1 min 5 arcsec	1 min 30 arcsec	3 min 29 arcsec	4 min 14 arcsec	10 min 10 arcsec

m_v = highest magnitude at the opposition; ap = maximum apparent geocentric distance to Saturn at opposition

The outer satellites
The outer satellites present also several families of satellites since some have retrograde orbits:

the direct satellites

the retrograde satellites (including S 9 - Phoebe)

The "direct" family: direct revolution

satellites:	a in km	P in years	eccentricity	inclination on the ecliptic	d in km	m_v	ap
S/2000 S5 - Kiviuq - S 24	11 319 009	1.23	0.1658184	48.39259°	14	22.1	0.54°
S/2000 S6 - Ijiraq - S 22	11 359 250	1.24	0.3592355	49.17794°	10	23.0	0.54°
S/2000 S2 - Paaliaq - S 20	14 985 054	1.88	0.4618653	45.86246°	18	21.6	0.71°
S/2000 S11 - Albiorix - S 26	16 495 933	2.17	0.4515501	37.40368°	21	20.3	0.78°
S/2004 S11 - Bebhionn - S 37	16 950 000	2.25	0.336	41.0°	6	24.1	0.80°
S/2007 S1	17 920 000	2.45	0.107	49.86°	7	23.9	0.84°
S/2000 S4 - Tarvos - S 21	17 977 236	2.46	0.6125237	34.90118°	12	22.2	0.86°
S/2000 S10 - Erriapo - S 28	17 807 712	2.43	0.6093181	34.47206°	8	23.2	0.85°
S/2000 S3 - Siarnaq - S 29	18 201 438	2.51	0.3804753	48.50265°	35	20.0	0.87°

a=semi-major axis; P= period of revolution; d=diameter; m_v= visual magnitude at opposition; ap= apparent semi major axis at opposition elements at epoch 2001 for S/2000 The "Phoebe" family: retrograde revolution

satellites:	a in km	P in years	eccentricity	inclination on the ecliptic	d in km	m_v	ap
Phoebe - S 9	12 893 240	1.496	0.17563	173.73°	230 x 220 x 210	16.5	0.61°
S/2000 S8 - Skathi - S 27	15 471 935	1.97	0.2117209	148.71370°	6	24.0	0.74°
S/2007 S2	16 560 000	2.19	0.218	176.7°	6	24.4	0.78°
S/2006 S8 - Skoll - S 47	17 610 000	2.38	0.418	155.6°	6	24.5	0.82
S/2006 S4	18 105 000	2.48	0.374	172.7°	6	24.4	0.86°
S/2004 S19 - Hyrokkin - S 44	18 217 125	2.50	0.360	153.3°	8	23,5	0.87°
S/2000 S9 - Mundilfari - S 25	18 412 670	2.55	0.2123419	169.79520°	5	23.8	0.88°
S/2004 S13	18 450 000	2.48	0.273	167.4°	6	24.5	0.88°
S/2004 S17	18 600 000	2.50	0.259	166.6°	4	25.2	0.89°
S/2004 S15 - Bergelmir - S 38	18 750 000	2.60	0.180	156.9°	6	24.2	0.90°
S/2006 S1	18 981 135	2.66	0.130	154.2°	6	24.6	0.90°
S/2003 S1 - Narvi - S 31	19 140 479	2.71	0.3254084	135.83163°	4.9	23.9	0.91°
S/2000 S12 - Suttungr - S 23	19 185 702	2.72	0.1445464	174.65113°	6	23.8	0.91°
S/2004 S10 - Aegir - S 36	19 350 000	2.81	0.241	167.0°	6	24.4	0.94°
S/2004 S12	19 650 000	2.87	0.401	164.0°	5	24.8	0.95°
S/2004 S18 - Bestla - S 39	19 650 000	2.88	0.795	147.4°	7	23.8	0.95°
S/2004 S9 - Farbauti - S 40	19 800 000	2.95	0.235	157.6°	5	24.7	0.95°
S/2004 S7	19 800 000	3.02	0.180	165.1°	6	24.5	0.95°
S/2004 S14 - Hati - S 43	19 950 000	2.96	0.292	162.7°	6	24.4	0.95°
S/2000 S7- Thrymr - S 30	19 957 538	2.88	0.5653018	174.91079°	6	23.5	0.95°
S/2007 S3	20 578 000	3.01	0.130	177.2°	5	24.9	0.98°
S/2006 S3	21 132 000	3.13	0.471	150.8°	6	24.6	1.00°
S/2004 S8 - Forjot - S 42	22 200 000	3.71	0.213	168°	6	24.6	1.09°
S/2004 S16 - Fenrir - S 41	22 200 000	3.48	0.135	163.0°	4	25.0	1.09
S/2006 S7 - Surtur - S 48	22 290 000	3.37	0.368	166.9°	6	24.8	1.10°
S/2006 S2 - Kari - S 45	22 350 000	3.41	0.341	148.4°	7	23.9	1.10°
S/2006 S5 - Loge - S 46	23 190 000	3.60	0.139	166.5°	6	24.6	1.11°
S/2006 S6	23 190 000	2.58	0.192	162.9°	6	24.7	1.11°
S/2000 S1 - Ymir - S 19	23 305 867	3.64	0.3746580	172.74556°	15	22.3	1.11°

a=semi-major axis; P= period of revolution; d=diameter; m_v= visual magnitude at opposition; ap= apparent semi major axis at opposition elements at epoch 2001 for S/2000

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