There is also an asteroid called 548 Kressida.

Cressida /ˈkrɛsədə/ is an inner satellite of Uranus. It was discovered from the images taken by Voyager 2 on 9 January 1986, and was given the temporary designation S/1986 U 3.[8] It was named after Cressida, the Trojan daughter of Calchas, a tragic heroine who appears in William Shakespeare's play Troilus and Cressida (as well as in tales by Geoffrey Chaucer and others). It is also designated Uranus IX.[9]

Cressida
Enhanced Voyager 2 image of Cressida
Discovery
Discovered byStephen P. Synnott / Voyager 2
Discovery dateJanuary 9, 1986
Designations
Designation
Uranus IX
Pronunciation/ˈkrɛsədə/[1]
Named after
Χρησίδα
AdjectivesCressidian /krɛˈsɪdiən/[2]
Orbital characteristics[3]
61,766.730 ± 0.046 km
Eccentricity0.00036 ± 0.00011
0.463569601 ± 0.000000013 d
Inclination0.006 ± 0.040° (to Uranus' equator)
Satellite ofUranus
Physical characteristics
Dimensions92 × 74 × 74 km[4][note 1]
~20000 km2[a]
Volume263800±38.0% km3[5]
Mass(1.839±0.212)×1017 kg[5]
Mean density
0.70+0.44
−0.21
 g/cm3
[5]
~0.006–0.009 m/s2[a]
~0.023–0.026 km/s[a]
synchronous[4]
zero[4]
Albedo0.08±0.005[6]
0.07[7]
Temperature~65 K[a]
  1. ^ Only two dimensions are known; the third dimension has been assumed to equal the smaller known dimension.

Cressida belongs to the Portia group of satellites, which includes Bianca, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda, and Perdita.[6] These satellites have similar orbits and photometric properties.[6] Other than its orbit,[3] size of 92 × 74 km,[4] and geometric albedo of 0.08,[6] virtually nothing is known about it.

In Voyager 2 imagery Cressida appears as an elongated object, with its major axis pointing towards Uranus. The ratio of axes of Cressida's prolate spheroid is 0.8 ± 0.3.[4] Its surface is grey in color.[4]

Cressida orbits close to a 3:2 resonance with the η ring, one of the rings of Uranus. Perturbations of the ring's shape provide a way to measure the mass of Cressida, which in 2024 was found to be (1.839±0.212)×1017 kg.[5] Cressida is one of the few small satellites of Uranus for which the mass has been directly measured.[10][5]

Cressida may collide with Desdemona within the next 100 million years.[11]

See also

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Notes

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  1. ^ a b c d Calculated on the basis of other parameters.

References

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  1. ^ Benjamin Smith (1903). The Century Dictionary and Cyclopedia.
  2. ^ Kellog (1995). Boccaccio's and Chaucer's Cressida.
  3. ^ a b Jacobson, R. A. (1998). "The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager 2 Observations". The Astronomical Journal. 115 (3): 1195–1199. Bibcode:1998AJ....115.1195J. doi:10.1086/300263. S2CID 118616209.
  4. ^ a b c d e f 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.
  5. ^ a b c d e French, Richard G.; Hedman, Matthew M.; Nicholson, Philip D.; Longaretti, Pierre-Yves; McGhee-French, Colleen A. (2024-03-15). "The Uranus system from occultation observations (1977–2006): Rings, pole direction, gravity field, and masses of Cressida, Cordelia, and Ophelia". Icarus. 411: 115957. arXiv:2401.04634. doi:10.1016/j.icarus.2024.115957. ISSN 0019-1035.
  6. ^ a b c d 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.
  7. ^ Williams, Dr. David R. (23 November 2007). "Uranian Satellite Fact Sheet". NASA (National Space Science Data Center). Retrieved 12 December 2008.
  8. ^ Smith, B. A. (January 16, 1986). "Satellites of Uranus". IAU Circular. 4164. Retrieved 29 October 2011.
  9. ^ "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. Retrieved 6 August 2006.
  10. ^ Chancia, Robert. A.; Hedman, Matthew M.; French, Richard G. (28 August 2017). "Weighing Uranus' moon Cressida with the η ring". The Astronomical Journal. 154 (4): 153. arXiv:1708.07566. Bibcode:2017AJ....154..153C. doi:10.3847/1538-3881/aa880e. S2CID 54827255.
  11. ^ Duncan, Martin J.; Lissauer, Jack J. (1997). "Orbital Stability of the Uranian Satellite System". Icarus. 125 (1): 1–12. Bibcode:1997Icar..125....1D. doi:10.1006/icar.1996.5568.
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