|Discovered by||Erich Karkoschka / Voyager 2|
|Discovery date||May 18, 1999 (in images dating back to January 18, 1986)|
|Mean orbit radius||76,417 ± 1 km1|
|Eccentricity||0.0012 ± 0.00051|
|Orbital period||0.638021 ± 0.000013 d1|
|Inclination||0.0 ± 0.3° (to Uranus' equator)1|
|Dimensions||30 × 30 × 30 km1|
|Mean radius||15 ± 3 km1|
|Surface area||~2,800 km² a|
|Volume||~14,000 km³ a|
|Mean density||~1.3 g/cm³ (assumed)|
|Equatorial surface gravity||~0.0047 m/s² a|
|Escape velocity||~0.011 km/sa|
|Albedo||0.08 ± 0.012|
Perdita (pron.: // PUR-di-tə) is an inner satellite of Uranus. Perdita's discovery was complicated. 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.13 But because no further pictures could be taken to confirm its existence, it was officially demoted in 2001.4 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.56
Following its discovery in 1999, it was given the temporary designation of S/1986 U 10.3 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.7
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. It is also close to an 8:7 resonance with Rosalind.15
Perdita belongs to Portia Group of satellites, which also includes Bianca, Cressida, Desdemona, Portia, Juliet, Cupid, Rosalind and Belinda.2 These satellites have similar orbits and photometric properties.2 Little is known about Perdita apart from its orbit,15 radius of 15 km1 and geometric albedo of 0.08.2
- Calculated on the basis of other parameters.
- Karkoschka, Erich (2001). "Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites". Icarus 151 (1): 69–77. Bibcode:2001Icar..151...69K. doi:10.1006/icar.2001.6597.
- Karkoschka, Erich (2001). "Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope". Icarus 151 (1): 51–68. Bibcode:2001Icar..151...51K. doi:10.1006/icar.2001.6596.
- Green, Daniel W. E. (May 18, 1999). "S/1986 U 10". IAU Circular 7171. ISSN 0081-0304. Retrieved 2012-01-26.
- Foust, Jeff (December 31, 2001). "Moon of Uranus is demoted". Spaceflight Now. Retrieved 2012-01-26.
- Showalter, Mark R.; Lissauer, Jack J. (2006-02-17). "The Second Ring-Moon System of Uranus: Discovery and Dynamics". Science 311 (5763): 973–977. Bibcode:2006Sci...311..973S. doi:10.1126/science.1122882. PMID 16373533.
- Green, Daniel W. E. (September 3, 2003). "Satellites of Uranus". IAU Circular 8194. ISSN 0081-0304. Retrieved 2012-01-26.
- USGS/IAU (July 21, 2006). "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. Retrieved 2012-01-26.