13 Moons

Full Moon
Distance from Sun
1.00 au
Semi-major axis
384 399 km
Orbital period
27.32 days
Mass
1022×7.342
Diameter
3 474.8 km
Mean density
3.344 g/cm3
Surface gravity
1.62 m/s2
Escape velocity
2 380 m/s
SatelliteOf
Earth and Moon
Io. Galileo, 3 July 1999

Io

Distance from Sun
5.20 au
Semi-major axis
421 700 km
Orbital period
1.77 days
Mass
1022×8.931938
Diameter
3 643.2 km
Mean density
3.528 g/cm3
Surface gravity
1.80 m/s2
Escape velocity
2 558 m/s
SatelliteOf
Jupiter and Io. Artist's impression
Europa. Galileo, September 7 1996
Distance from Sun
5.20 au
Semi-major axis
670 900 km
Orbital period
3.55 days
Mass
1022×7.342
Diameter
3 121.6 km
Mean density
3.013 g/cm3
Surface gravity
1.31 m/s2
Escape velocity
2 025 m/s
SatelliteOf
Europa Water Vapor Plume. Artist's Concept
Ganymede. Galileo, 29 March 1998
Distance from Sun
5.20 au
Semi-major axis
1 070 400 km
Orbital period
7.15 days
Mass
1023×1.4819
Diameter
5 268.2 km
Mean density
1.936 g/cm3
Surface gravity
1.43 m/s2
Escape velocity
2 741 m/s
SatelliteOf
Ganymede and Jupiter. Artist concept
Callisto. Galileo, 22 August 2001
Distance from Sun
5.20 au
Semi-major axis
1 882 700 km
Orbital period
16.69 days
Mass
1023×1.075 938
Diameter
4 820.6 km
Mean density
1.834 g/cm3
Surface gravity
1.24 m/s2
Escape velocity
2 440 m/s
SatelliteOf
Callisto. Voyager 1, March 6, 1979
Cassini mosaic of Rhea
Distance from Sun
9.55 au
Semi-major axis
527 108 km
Orbital period
4.52 days
Mass
1021×2.306 518
Diameter
1 528.6 km
Mean density
1.236 g/cm3
Surface gravity
0.26 m/s2
Escape velocity
635 m/s
SatelliteOf
Rhean rings. Artist's conception
Titan. Cassini, Jan. 30, 2012
Distance from Sun
9.55 au
Semi-major axis
1 221 870 km
Orbital period
15.95 days
Mass
1023×1.3452
Diameter
5 150.0 km
Mean density
1.880 g/cm3
Surface gravity
1.35 m/s2
Escape velocity
2 639 m/s
SatelliteOf
Titan and rings of Saturn
Iapetus. Cassini, 2004
Distance from Sun
9.55 au
Semi-major axis
3 560 820 km
Orbital period
79.32 days
Mass
1021×1.805635
Diameter
1 436.0 km
Mean density
1.088 g/cm3
Surface gravity
0.22 m/s2
Escape velocity
573 m/s
SatelliteOf
Iapetus equatorial ridge
Titania. Voyager 2, Jan. 24, 1986
Distance from Sun
19.22 au
Semi-major axis
435 910 km
Orbital period
8.71 days
Mass
1021×3.527
Diameter
1 576.8 km
Mean density
1.711 g/cm3
Surface gravity
0.38 m/s2
Escape velocity
773 m/s
SatelliteOf
Titania with surface features labeled
Oberon. Voyager 2, Jan. 24, 1986
Distance from Sun
19.22 au
Semi-major axis
583 520 km
Orbital period
13.46 days
Mass
1021×3.014
Diameter
1 522.8 km
Mean density
1.630 g/cm3
Surface gravity
0.35 m/s2
Escape velocity
727 m/s
SatelliteOf
Artist's rendition of Oberon, closes Uranus
Umbriel as seen by Voyager 2 in 1986
Distance from Sun
19.22 au
Semi-major axis
266 000 km
Orbital period
4.14 days
Mass
1021×1.172
Diameter
1 169.4 km
Mean density
1.390 g/cm3
Surface gravity
0.20 m/s2
Escape velocity
520 m/s
SatelliteOf
Uranus and Umbriel
Triton. Voyager 2, 25 August 1989
Distance from Sun
30.11 au
Semi-major axis
354 759 km
Orbital period
5.88 days
Mass
1022×2.14
Diameter
2 706.8 km
Mean density
2.061 g/cm3
Surface gravity
0.78 m/s2
Escape velocity
1 455 m/s
SatelliteOf
Triton. Artist's impression
Charon, New Horizons 13 July 2015
Distance from Sun
39.54 au
Semi-major axis
19 571 km
Orbital period
6.39 days
Mass
1021×1.586
Diameter
1 208.0 km
Mean density
1.707 g/cm3
Surface gravity
0.29 m/s2
Escape velocity
604 m/s
SatelliteOf
Pluto and Charon