Astronomy:Perdita (moon)

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Short description: Moon of Uranus
Perdita
Perdita feat.jpg
Discovery
Discovered byErich Karkoschka / Voyager 2
Discovery dateMay 18, 1999 (in images dating back to January 18, 1986)
Designations
Designation
Uranus XXV
Pronunciation/ˈpɜːrdətə/[1]
AdjectivesPerditean /pɜːrdəˈtən/[2]
Orbital characteristics
Mean orbit radius76,417 ± 1 km[3]
Eccentricity0.0012 ± 0.0005[3]
Orbital period0.638021 ± 0.000013 d[3]
Inclination0.0 ± 0.3° (to Uranus' equator)[3]
Satellite ofUranus
Physical characteristics
Dimensions30 × 30 × 30 km[3]
Mean radius15 ± 3 km[3]
Surface area~2,800 km2[lower-alpha 1]
Volume~14,000 km3[lower-alpha 1]
Mass~0.18×1017 kg[lower-alpha 1]
Mean density~1.3 g/cm3 (assumed)
~0.0047 m/s2[lower-alpha 1]
~0.011 km/s[lower-alpha 1]
Rotation periodsynchronous[3]
Axial tiltzero[3]
Albedo0.08 ± 0.01[4]
Physics~64 K[lower-alpha 1]


Perdita /ˈpɜːrdətə/ is an 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.[3][5] But because no further pictures could be taken to confirm its existence, it was officially demoted in 2001.[6] 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.[7][8]

Following its discovery in 1999, it was given the temporary designation of S/1986 U 10.[5] 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.[9]

Discovery image of Perdita taken by Voyager 2 on 23 January 1986. The location of the moon is indicated by the arrow on the upper right.

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.[3][7]

Perdita belongs to the Portia group of satellites, which also includes Bianca, Cressida, Desdemona, Portia, Juliet, Cupid, Rosalind and Belinda.[4] These satellites have similar orbits and photometric properties.[4] Little is known about Perdita apart from its orbit,[3][7] radius of 15 km[3] and geometric albedo of 0.08.[4]

See also

References

Explanatory notes

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Calculated on the basis of other parameters.

Citations

  1. Benjamin Smith (1903) The Century Dictionary and Cyclopedia
  2. Byrne (2008) Perdita: the literary, theatrical, scandalous life of Mary Robinson
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 Karkoschka, Voyager 2001.
  4. 4.0 4.1 4.2 4.3 Karkoschka, Hubble 2001.
  5. 5.0 5.1 IAUC 7171.
  6. Foust 2001.
  7. 7.0 7.1 7.2 Showalter & Lissauer 2006.
  8. IAUC 8194.
  9. USGS: Planet and Satellite Names and Discoverers.

Sources

External links