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Uranus's natural satellites
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Uranus's natural satellites

Uranus has 27 known moonss.

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

All moons of Uranus are named after characters from Shakespeare or Alexander Pope. Titania and Oberon are characters from Shakespeare's A Midsummer Nights Dream.

The flyby of the Voyager 2 space probe in January 1986 led to the discovery of a further 10 moons, and another satellite S/1986 U 10 was later found after studying old Voyager photographs. Eleven additional moons have since been identified using telescopes.

Uranus's natural satellites
Name Diameter (km) Mass (kg) Mean orbital
radius (km)
Orbital period
Cordelia 40 4.5 × 1016 ? 49,770 0.335034 days
Ophelia 42 5.4 × 1016 ? 53,790 0.376400 days
Bianca 51 9.3 × 1016 ? 59,170 0.434579 days
Cressida 80 3.43 × 1017 ? 61,780 0.463570 days
Desdemona 64 1.78 × 1017 ? 62,680 0.473650 days
Juliet 93 5.57 × 1017 ? 64,350 0.493065 days
Portia 135 1.68 × 1018 ? 66,090 0.513196 days
Rosalind 72 2.54 × 1017 ? 69,940 0.558460 days
S/2003 U 2* 10 Unknown 74,800 0.618 days
Belinda 80 3.57 × 1017 ? 75,260 0.623527 days
S/1986 U 10* 20 Unknown 76,420 0.638 days
Puck 162 2.89 × 1018 ? 86,010 0.761833 days
S/2003 U 1* 10 Unknown 97,734 0.923 days
Miranda 472 6.6 × 1019 129,390 1.413479 days
Ariel 1158 1.35 × 1021 191,020 2.520379 days
Umbriel 1170 1.17 × 1021 266,300 4.144177 days
Titania 1578 3.52 × 1021 435,910 8.705872 days
Oberon 1523 3.01 × 1021 583,520 13.463239 days
S/2001 U 3* 12 Unknown 4,276,000 -266.6 days**
Caliban 98 7.3 × 1017 ? 7,231,000 -579.7 days**
Stephano 20 6 × 1015 ? 8,004,000 -677.4 days**
Trinculo 10 Unknown 8,504,000 -759.0 days**
Sycorax 190 5.4 × 1018 ? 12,179,000 -1288.3 days**
S/2003 U 3* 11 Unknown 14,345,000 1694.8 days
Prospero 30 2.1 × 1016 ? 16,256,000 -1977.3 days**
Setebos 30 2.1 × 1016 ? 17,418,000 -2234.8 days**
S/2001 U 2* 12 Unknown 20,901,000 -2823.4 days**

*Awaiting confirmation and naming

**negative orbital periods indicate a retrograde orbit around Uranus (opposite to the planet's rotation)

Sources: [1], [1]

Note: These sources give no information on the masses for the small satellites; some data have changed greatly so it is unlikely that these old values are correct.

Naming notes

Some asteroids share the same names as moons of Uranus: 171 Ophelia, 218 Bianca, 593 Titania, 666 Desdemona, 2758 Cordelia.

See also


Uranus
Puck's group | Miranda | Ariel | Umbriel
Titania | Oberon | Sycorax's group | S/2003 U 3
(For other moons, see: Uranus's natural satellites)