The Satellites of Uranus

Details about the 27 moons of Uranus

Name	Diameter(s) (km)	Mean Distance From Planet (×10³ km)	Rotational Period (days)	Orbital Period (days)	Orbital Inclination	Orbital Eccentricity	Albedo (%)
Small Regular Direct Satellites
Cordelia	40	49.77		0.335034	0.085°	0.0003	7
Ophelia	42	53.79		0.376400	0.104°	0.0099	7
Bianca	51	59.17		0.434579	0.193°	0.0009	7
Cressida	80	61.78		0.463570	0.006°	0.0004	7
Desdemona	64	62.68		0.473650	0.113°	0.0001	7
Juliet	93	64.35		0.493065	0.065°	0.0007	7
Portia	135	66.09		0.513196	0.059°	0.0000	7
Rosalind	72	69.94		0.558460	0.279°	0.0001	7
S/2003 U2	10	74.80		0.62	0.0°	0.0
Belinda	80	75.26		0.623527	0.031°	0.0001	7
S/1986 U10	20	76.42		0.638	0.0°	0.0
Puck	162	86.01		0.761833	0.319°	0.0001	7
S/2003 U1	10	97.73			0.0°	0.0
Larger Regular Direct Satellites
Miranda	480 × 468.4 × 465.8	129.39	1.413479	1.413479	4.338°	0.0027	27
Ariel	1162 × 1156 × 1155	191.02	2.520379	2.520379	0.041°	0.0034	35
Umbriel	1,169.4	266.30	4.144177	4.144177	0.128°	0.0050	19
Titania	1,577.8	435.91	8.705872	8.705872	0.079°	0.0022	28
Oberon	1,522.8	583.52	13.463239	13.463239	0.068°	0.0008	25
Outer Iregular Satellites
S/2001 U3	22	4,276		-266.6	145.2°	0.146
Caliban	72	7,231		-579.7	140.9°	0.159	7
Stephano	32	8,004		-677.4	144.1°	0.229
Trinculo	18	8,504		-759.0	167.1°	0.220
Sycorax	150	12,179		-1,288	159.4°	0.522	7
S/2003 U3	20	14,345		1,694	56.6°	0.661
Prospero	50	16,256		-1,977	152.0°	0.445
Setebos	47	17,418		-2,235	158.2°	0.591
S/2001 U2	21	20,901		2,823	169.8°	0.368

Name

The satellites of Uranus have names associated with Shakesperean characters. Un-named satellites are in blue.

Diameter

Apart from Miranda, Ariel, Umbriel, Titania and Oberon, all the satellites of Uranus are small bodies. Even the "big" five are among the smaller of the satellites of the Solar System.

Mean Distance From Planet

The satellites are all fairly evenly spaced out.

Rotational and Orbital Periods

The big five of Uranus' satellites rotate in the same period as they revolve around the planet. This is caused by the strong tidal forces exerted by the planet on the satellite. The outer satellites are less affected by tidal forces.

As seen from above the north pole of the Earth, most of the planets and satellites revolve in an anticlockwise direction. This is called Direct or Prograde Motion. Some satellites revolve in a clockwise sense. This is called Retrograde Motion and is shown by the presence of a minus sign. All but one of the outer satellites revolve around Uranus in the retrograde direction.

Orbital Inclination

This is the angle of inclination of the satellite orbits compared to the planet's equatorial plane. Most of Uranus' satellites orbit very close to the planet's equator. Note that Uranus' equator is inclined virtually at right angles to the planet's orbital plane. The satellites follow this strange inclination. The outer satellites are the exceptions.

Orbital Eccentricity

The orbits of Uranus' inner satellites are nearly circular. The outer ones have eccentric orbits.

Albedo

This is the percentage of sunlight that is reflected by the satellites. Most of Uranus' satellites are dark bodies.

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