Perdita (moon)

Perdita /ˈpɜːrdətə/ is a small inner satellite of Uranus. Perdita's discovery was very complicated, as the first photographs of Perdita were taken by the Voyager 2 spacecraft in 1986, but it was not recognized from the photographs for more than a decade. In 1999, the moon was noticed by Erich Karkoschka and reported.^[4][9] However, because no further pictures could be taken to confirm its existence, it was officially demoted in 2001.^[10] However, in 2003, pictures taken by the Hubble Space Telescope managed to pick up an object where Perdita was supposed to be, finally confirming its existence.^[8][11]

Following its discovery in 1999, it was given the temporary designation of S/1986 U 10.^[9] It was named Perdita (Latin for 'lost') after the daughter of Leontes and Hermione in William Shakespeare's play The Winter's Tale. The moon is also designated Uranus XXV.^[12]

The moon orbits between Belinda and Puck. The above-mentioned Hubble measurements prove that Perdita does not follow a direct Keplerian motion around Uranus. Instead, it is clearly caught in a 43:44 orbital resonance with the nearby moon Belinda, and from this resonance it has been determined that Belinda's mass is 26^[13] or 27^[7] times that of Perdita. It is also close to an 8:7 resonance with Rosalind.^[4][8]

Perdita belongs to the Portia group of satellites, which also includes Bianca, Cressida, Desdemona, Portia, Juliet, Cupid, Rosalind, and Belinda.^[14] These satellites have similar orbits and photometric properties.^[14] Little is known about Perdita apart from its orbit,^[4][8] radius of 13.3 km (8.3 mi),^[5] and geometric albedo of 0.08.^[14][8]