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Uranus' moons are named after Shakespearian characters.


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Uranus has 27 known moons. The first two moons (Titania and Oberon) were discovered by William Herschel on March 13, 1787. Two more Uranus moons (Ariel and Umbriel) were discovered by William Lassell in 1851. In 1852, Herschel's son John Herschel gave the four then-known Uranus moons their names. In 1948 Gerard Kuiper discovered the moon Miranda.

Uranus moons.
Irregular moons of Uranus.

The flyby of the Voyager 2 space probe in January 1986 led to the discovery of a further 10 inner moons, and another satellite Perdita was later found after studying old Voyager photographs. Two more small inner moons were discovered by astronomers using the Hubble Space Telescope. Until 1997, Uranus was the only giant planet with no known irregular satellites. Since then, nine distant irregular moons have been identified using ground-based telescopes.

The region between the main rings and Miranda appears to be very crowded. The small moons there are constantly perturbed by each other. The system is chaotic and apparently unstable, and simulations show that the moons may perturb each other into crossing orbits which may result in collisions between the moons.

Unlike most planetary moons, which are named from antiquity, all the moons of Uranus are named after characters from the works of Shakespeare and Alexander Pope.

The natural satellites of Uranus.

moons of Uranus.
Major moons of Uranus compared, at their proper relative sizes.

The Uranian moons are listed here by orbital period, from shortest to longest. Moons massive enough for their surfaces to have collapsed into a spheroid are highlighted in light blue. Irregular (captured) moons with prograde orbits are shown in light grey, those with retrograde orbits in dark grey.

Notes: * Awaiting confirmation and naming; ** Negative orbital periods indicate a retrograde orbit around Uranus (opposite to the planet's rotation).
OrderName (spheroidal moons in bold)

(Pronunciation key)

ImageMean diameter (km)Mass (kg)Semi-major
axis (km)
Orbital period (day)Inclination (º)
(to Uranus' equator)
Discovery date
1 Uranus VI Cordelia 40 6 4.51016? 49,770 0.335034 1986
2 Uranus VII Ophelia 43 8 5.41016? 53,790 0.376400 1986
3 Uranus VIII Bianca 51 4 9.31016? 59,170 0.434579 1986
4 Uranus IX Cressida 80 4 3.431017? 61,780 0.463570 1986
5 Uranus X Desdemona 64 8 1.781017? 62,680 0.473650 1986
6 Uranus XI Juliet 94 8 5.571017? 64,350 0.493065 1986
7 Uranus XII Portia 135 8 1.681018? 66,090 0.513196 1986
8 Uranus XIII Rosalind 72 12 2.541017? 69,940 0.558460 1986
9 Uranus XXVII Cupid ~ 17.8 3.81015? 74,800 0.618 2003
10 Uranus XIV Belinda 81 16 3.571017? 75,260 0.623527 1986
11 Uranus XXV Perdita ~ 26.6 1.31016? 76,420 0.638 1986
12 Uranus XV Puck
uranus moon puck.
162 4 2.891018? 86,010 0.761833 1985
13 Uranus XXVI Mab ~ 24.8 1.01016? 97,734 0.923 2003
14 Uranus V Miranda
uranus moon miranda.
471.6 1.4 (6.6 0.7)1019 129,390 1.413479 1948
15 Uranus I Ariel
uranus moon ariel.
1157.8 1.2 (1.35 0.12)1021 191,020 2.520379 1851
16 Uranus II Umbriel
uranus moon umbriel.
1169.4 5.6 (1.17 0.13)1021 266,300 4.144177 1851
17 Uranus III Titania
uranus moon titania.
1577.8 3.6 (3.53 0.09)1021 435,910 8.705872 1787
18 Uranus IV Oberon
uranus moon oberon.
1522.8 5.2 (3.01 0.07)1021 583,520 13.463239 1787
19 Uranus XXII Francisco ~ 12 1.31015? 4,276,000 -267.12** 147.459º 2001
20 Uranus XVI Caliban ~ 98 7.31017? 7,231,000 -579.39** 139.885º 1997
21 Uranus XX Stephano ~ 20 61015? 8,004,000 -677.48** 141.873º 1999
22 Uranus XXI Trinculo ~ 10 7.51014? 8,504,000 -748.83** 166.252º 2001
23 Uranus XVII Sycorax ~ 190 5.41018? 12,179,000 -1285.62** 152.456º 1997
24 Uranus XXIII Margaret ~ 11 1.31015? 14,345,000 +1654.32 51.455º 2003
25 Uranus XVIII Prospero ~ 30 2.11016? 16,256,000 -1962.95** 146.017º 1999
26 Uranus XIX Setebos ~ 30 2.11016? 17,418,000 -2196.35** 145.883º 1999
27 Uranus XXIV Ferdinand ~ 12 1.31015? 20,901,000 -2805.51** 167.346º 2001

Sources: NASA/NSSDC, University of Hawaii and Natural Satellites Ephemeris Service (for the outer satellites). These sources give no information on the masses for the small satellites.

Irregular satellites or moons of Uranus.

The diagram illustrates the orbits of the Irregular satellites of Uranus discovered so far. The eccentricity of the orbits is represented by the yellow segments (extending from the pericentre to the apocentre) with the inclination represented on Y axis. The satellites above the axis are prograde, the satellites beneath are retrograde. The X axis is labelled in Gm (million km) and the fraction of the Hill sphere's (gravitational influence) radius (approximately 70 million km for Uranus).

Unlike for Jupiter's irregulars, no correlation axis versus inclination can be found among the known population. Instead, the retrograde moons can be divided into two groups based on axis/eccentricity. The inner group includes satellites closer to Uranus (a < 0.15 rH) and moderately eccentric (~0.2), namely: Francisco, Caliban, Stephano and Trinculo. The outer group (a > 0.15 rH) includes satellites with high eccentricity (~0.5): Sycorax, Prospero, Setebos and Ferdinand.

Naming notes for Uranus moons.

Some asteroids share the same names as moons of Uranus: 171 Ophelia, 218 Bianca, 593 Titania, 666 Desdemona, 763 Cupido and 2758 Cordelia. See also Name conflicts of solar system bodies.




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