Planetary Satellite Physical Parameters

The following table lists currently available physical parameters for planetary satellites. Tables are grouped by planet. Table column headings are described below.

Satellites of Earth

Planet GM: 398600.436 ± 0.001 km³ s^-2 (ref: DE440)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Moon	4902.800 ±0.001 [DE440]	1737.4 ±0.1 [1]	3.344 ±0.001 [*]

Satellites of Mars

Planet GM: 42828.37362 ± 0.0008 km³ s^-2 (ref: MAR097)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Phobos	0.0007087 ±0.0000006 [MAR097]	11.08 ±0.04 [1]	1.872 ±0.076 [*]
Deimos	0.0000962 ±0.0000028 [MAR097]	6.2 ±0.24 [1]	1.471 ±0.166 [*]

Satellites of Jupiter

Planet GM: 126686531.9 ± 0.42 km³ s^-2 (ref: JUP365)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Io	5959.91547 ±0.00135 [JUP365]	1821.49 ±0.50 [1]	3.5276 ±0.0029 [*]
Europa	3202.71210 ±0.00181 [JUP365]	1560.80 ±0.30 [1]	3.0130 ±0.0017 [*]
Ganymede	9887.83275 ±0.00247 [JUP365]	2631.20 ±1.70 [1]	1.9416 ±0.0038 [*]
Callisto	7179.28340 ±0.00324 [JUP365]	2410.30 ±1.50 [1]	1.8340 ±0.0034 [*]
Amalthea	0.16456 ±0.00867 [JUP365]	83.50 ±3.00 [1]	1.0111 ±0.1213 [*]
Thebe	0.03015 ±0.01250 [JUP365]	49.30 ±4.00 [1]	0.9000 ±0.4327 [*]
Adrastea	0.00014 ±0.00020 [JUP365]	8.20 ±4.00 [1]	0.9018 ±1.8507 [*]
Metis	0.00250 ±0.00160 [JUP365]	21.50 ±4.00 [1]	0.9002 ±0.7642 [*]
Himalia	0.15155 ±0.05763 [JUP344]	85.00 ±10.00 [1]	0.8827 ±0.4580 [*]

Satellites of Saturn

Planet GM: 37931206.23 ± 0.24 km³ s^-2 (ref: SAT441)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Mimas	2.50349 ±0.00014 [SAT441]	198.20 ±0.40 [1]	1.1501 ±0.0070 [*]
Enceladus	7.21037 ±0.00009 [SAT441]	252.10 ±0.20 [1]	1.6097 ±0.0038 [*]
Tethys	41.21353 ±0.00031 [SAT441]	531.10 ±0.60 [1]	0.9840 ±0.0033 [*]
Dione	73.11607 ±0.00005 [SAT441]	561.40 ±0.40 [1]	1.4781 ±0.0032 [*]
Rhea	153.94175 ±0.00041 [SAT441]	763.50 ±0.60 [1]	1.2372 ±0.0029 [*]
Titan	8978.13710 ±0.00025 [SAT441]	2574.76 ±0.02 [1]	1.8814 ±0.0001 [*]
Hyperion	0.37049 ±0.00005 [SAT441]	135.00 ±4.00 [1]	0.5386 ±0.0479 [*]
Iapetus	120.51511 ±0.00242 [SAT441]	734.30 ±2.80 [1]	1.0887 ±0.0125 [*]
Phoebe	0.55479 ±0.00108 [SAT441]	106.50 ±0.70 [1]	1.6428 ±0.0326 [*]
Janus	0.12662 ±0.00007 [SAT415]	89.2 ±0.8 [1]	0.6381 ±0.0172 [*]
Epimetheus	0.03514 ±0.00002 [SAT415]	58.2 ±1.2 [1]	0.6375 ±0.0394 [*]
Helene	0.00048 ±0.00002 [SAT441]	18.00 ±0.40 [1]	0.2918 ±0.0217 [*]
Atlas	0.00037 ±0.00001 [SAT415]	15.1 ±0.8 [1]	0.3850 ±0.0613 [*]
Prometheus	0.01071 ±0.00001 [SAT415]	43.1 ±1.2 [1]	0.4784 ±0.0400 [*]
Pandora	0.00926 ±0.00002 [SAT415]	40.6 ±1.5 [1]	0.4948 ±0.0549 [*]
Pan	0.00028 ±0.00014 [SAT415]	14.0 ±1.2 [1]	0.3650 ±0.2052 [*]

Satellites of Uranus

Planet GM: 5793951.3 ± 4.4 km³ s^-2 (ref: URA111)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Ariel	83.5 ±1.4 [URA111]	578.9 ±0.6 [1]	1.539 ±0.026 [*]
Umbriel	85.1 ±1.9 [URA111]	584.7 ±2.8 [1]	1.523 ±0.041 [*]
Titania	226.9 ±4.1 [URA111]	788.9 ±1.8 [1]	1.653 ±0.032 [*]
Oberon	205.3 ±5.8 [URA111]	761.4 ±2.6 [1]	1.664 ±0.050 [*]
Miranda	4.3 ±0.2 [URA111]	235.8 ±0.7 [1]	1.178 ±0.053 [*]

Satellites of Neptune

Planet GM: 6835099.97 ± 9.63 km³ s^-2 (ref: NEP097)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Triton	1428.49546 ±0.61603 [NEP097]	1352.60 ±2.40 [1]	2.0649 ±0.0110 [*]
Nereid	0.00000 ±0.00000 [NEP101]	170.00 ±25.00 [1]	n/a
Naiad	0.00853 ±0.00480 [NEP097]	29.00 ±6.00 [1]	1.2511 ±1.0478 [*]
Thalassa	0.02359 ±0.00522 [NEP097]	40.00 ±8.00 [1]	1.3184 ±0.8432 [*]
Despina	0.11673 ±0.25263 [NEP097]	74.00 ±10.00 [1]	1.0304 ±2.2689 [*]
Galatea	0.18990 ±0.76278 [NEP097]	79.00 ±12.00 [1]	1.3777 ±5.5695 [*]
Larissa	0.25484 ±3.12230 [NEP097]	96.00 ±7.00 [1]	1.0303 ±12.626 [*]
Proteus	2.58342 ±2.42070 [NEP097]	208.00 ±8.00 [1]	1.0269 ±0.9695 [*]

Satellites of Pluto

Planet GM: 869.3 ± 0.4 km³ s^-2 (ref: PLU060)

Satellite	GM (km³/s²)	Mean Radius (km)	Mean Density (g/cm³)
Charon	106.1 ±0.3 [PLU060]	606.0 ±0.5 [2]	1.853 ±0.004 [*]
Nix	0.0015 ±0.0005 [PLU060]	18.0 ±1.0 [3]	0.88 ±0.31 [*]
Hydra	0.0020 ±0.0003 [PLU060]	18.5 ±1.0 [3]	1.21 ±0.19 [*]
Kerberos	<0.0002 [PLU060]	6.0 ±1.0 [3]	n/a
Styx	<0.0003 [PLU060]	5.2 ±1.0 [3]	n/a

Notes

GM of the satellite is taken from the specified ephemeris.
Mean Radius references are listed below.
[ ref=* ] Mean Density is derived from the specified GM and Mean Radius.

Table Column Descriptions

GM	See glossary definition of GM.
Mean Radius	Radius of a sphere with the equivalent volume of the planetary satellite.
Mean Density	Density computed using the volume of a sphere with the specified `mean radius` and mass (derived from `GM`) of the planet.

Mean Radius References

B. A. Archinal, C. H. Acton, M. F. A’Hearn, et al. (2018) "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015". Celest.~Mech. 130:22.
Francis Nimmo, Orkan Umurhan, Carey M. Lisse, Carver J. Bierson, Tod R. Lauer, Marc W. Buie, Henry B. Throop, Josh A. Kammer, James H. Roberts, William B. McKinnon, Amanda M. Zangari, Jeffrey M. Moore, S. Alan Stern, Leslie A. Young, Harold A. Weaver, Cathy B. Olkin, Kim Ennico (2017) "Mean radius and shape of Pluto and Charon from New Horizons images". Icarus 287:12-29.
S. Alan Stern, William M. Grundy, William B. McKinnon, Harold A. Weaver, Leslie A. Young (2018) "The Pluto System After New Horizons". Annual Review of Astronomy and Astrophysics 56:357-392.
R. A. Jacobson (2021) "The Orbits of the Regular Jovian Satellites and the Orientation of the Pole of Jupiter". submitted to AJ : .
R. A. Jacobson (2021) "The Orbits of the Major Saturnian Satellites,the Trajectories of Spacecraft at Saturn, the Gravity Field of the Saturnian System, and the Orientation of Saturn's Pole". personal communication to Horizons/NAIF.