moons of Uranus
Moons of Uranus.
Features in the Uranus system. Credit: NASA, ESA, and A. Feild (STScI).
Uranus has 27 known moons, placing it third, by this reckoning, behind Jupiter (69) and Saturn (62). The first two were discovered by William Herschel in 1787, and named, by his son, after characters from Shakespeares A Midsummer Nights Dream, Titania and Oberon. Two more moons were found by William Lassell in 1851 and named Ariel and Umbriel; G. Kuiper discovered Miranda in 1948. All the moons of Uranus are named after characters from Shakespeare or Alexander Pope. Voyager 2s flyby in January 1986 led to the discovery of another 10. Twelve additional moons have since been discovered by telescope.
In an unusual move, in late 2001, the International Astronomical Union stripped the title of moon from a small body seen in images taken by Voyager and previously reported to be orbiting Uranus. The IAU concluded that there wasn't yet enough data to confirm that the object, designated S/1986 U10, is a satellite. It appeared to be in nearly the same orbit as another moon, Belinda, about 75,000 km from Uranus, and, based on its brightness in the Voyager images, to have a diameter of about 40 kilometers. S/1986 U 10 has not been seen since the Voyager 2 discovery, despite observing efforts that have discovered several other small moons orbiting the planet.
Two of the most recently discovered satellites, Cupid (S/2003 U1) and Mab (S/2003 U2), belong to the inner collection of satellites, each orbiting Uranus in less than a day. Indeed, it's hard to understand how the inner swarm of 13 Uranian moons, which are so close together that they must be gravitationally unstable, can coexist. All the moons from S2001/U3 out move in retrograde orbits. Click on each of the satellite names that appear in orange in the table below for further information.
|Cordelia||49,750||0.335||0.0003||0.085||50 × 36|
|Ophelia||53,760||0.376||0.0099||0.104||54 × 38|
|Bianca||59,170||0.435||0.0009||0.193||64 × 46|
|Cressida||61,770||0.464||0.0004||0.006||92 × 74|
|Desdemona||62,660||0.474||0.0001||0.113||90 × 54|
|Juliet||64,360||0.493||0.0007||0.065||150 × 74|
|Portia||66,100||0.513||0.0001||0.060||156 × 126|
|Rosalind||69,930||0.558||0.0001||0.279||72 × 72|
|Belinda||75,260||0.624||0.0001||0.031||81 ± 16|
|Perdita||76,420||0.638||0.0012||0.0||30 × 30|
|Puck||86,000||0.762||0.0001||0.319||162 ± 4|