Cressida (pronounced /ˈkrɛsɨdə/ KRES-i-də) 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.[7] It was named after 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.[8]
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] Unfortunately, other than its orbit,[1] radius of 41 km[2] and geometric albedo of 0.08[6] virtually nothing is known about it.
At the Voyager 2 images Cressida appears as an elongated object, the major axis pointing towards Uranus. The ratio of axises of the Cressida's prolate spheroid is 0.8 ± 0.3.[2] Its surface is grey in color.[2]
Cressida may collide with Desdemona within the next 100 million years.[9]
See also
* Moons of Uranus
References
1. ^ a b c d e Jacobson, R.A. (1998). "The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager 2 Observations". The Astronomical Journal 115: 1195–1199. doi:10.1086/300263. http://adsabs.harvard.edu/abs/1998AJ....115.1195J. edit
2. ^ a b c d e f g Karkoschka, Erich (2001). "Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites". Icarus 151: 69–77. doi:10.1006/icar.2001.6597. http://adsabs.harvard.edu/abs/2001Icar..151...69K. edit
3. ^ a b c "Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 24 October 2008. http://ssd.jpl.nasa.gov/?sat_phys_par. Retrieved 12 December 2008.
4. ^ a b Williams, Dr. David R. (23 November 2007). "Uranian Satellite Fact Sheet". NASA (National Space Science Data Center). http://nssdc.gsfc.nasa.gov/planetary/factsheet/uraniansatfact.html. Retrieved 12 December 2008.
5. ^ a b c d e f Calculated on the basis of other parameters
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: 51–68. doi:10.1006/icar.2001.6596. http://adsabs.harvard.edu/abs/2001Icar..151...51K. edit
7. ^ Smith, B. A. (16 January 1986). "IAU Circular No. 4164". http://cfa-www.harvard.edu/iauc/04100/04164.html#Item1. Retrieved 6 August 2006.
8. ^ "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. 21 July 2006. http://planetarynames.wr.usgs.gov/append7.html. Retrieved 6 August 2006.
9. ^ Duncan, Martin J.; Jack J. Lissauer (1997). "Orbital Stability of the Uranian Satellite System". Icarus 125 (1): 1–12. doi:10.1006/icar.1996.5568.
External links
* Cressida Profile by NASA's Solar System Exploration
* Uranus' Known Satellites (by Scott S. Sheppard)
Moons of Uranus