Moons of Uranus¹

name mean distance from centre of planet (orbital radius; km) orbital period (sidereal period; Earth days) inclination of orbit to planet's equator (degrees) eccentricity

of orbit rotation period² radius or radial dimensions (km)³ mass (kg) mean density (g/cm³)

Cordelia 49,752 0.335 0.08 0.0003 (13)

Ophelia 53,763 0.376 0.10 0.0099 (16)

Bianca 59,166 0.435 0.19 0.0009 (22)

Cressida 61,767 0.464 0.01 0.0004 (33)

Desdemona 62,658 0.474 0.11 0.0001 (29)

Juliet 64,358 0.493 0.07 0.0007 (42)

Portia 66,097 0.513 0.06 0.0000 (55)

Rosalind 69,927 0.558 0.28 0.0001 (29)

Belinda 75,256 0.624 0.03 0.0001 (34)

Puck 86,004 0.762 0.32 0.0001 (77)

Miranda 129,800 1.413 4.22

0.0027 sync. 240 x 234 x 233 6.6 x 10¹⁹ 1.20

Ariel 191,240 2.520 0.31

0.0034 sync. 581 x 578 x 578 1.35 x 10²¹ 1.67

Umbriel 265,970 4.144 0.36

0.0050 sync. 585 1.17 x 10²¹ 1.40

Titania 435,840 8.706 0.14

0.0022 sync. 789 3.52 x 10²¹ 1.71

Oberon 582,600 13.463 0.10

0.0008 sync. 761 3.01 x 10²¹ 1.63

¹Beginning in 1997, 11 additional moons were discovered with electronic detectors in Earth-based observations; a 12th moon was captured in Voyager 2 images but was not noticed until 1999 and not confirmed until 2003. Of this group, nine moons have large orbital radii, eccentricities, and inclinations; all but one also have retrograde orbits. The other three moons move in a prograde direction near the orbits of Belinda and Puck. Rough size estimates based on brightness place them all between 5 and 95 km in radius. They were assigned provisional numerical designations on discovery; several have received official names.

²Sync. = synchronous rotation; the rotation and orbital periods are the same.

³Quantities given in parentheses are uncertain by more than 10%.