Cressida (moon)

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There is also an asteroid called 548 Kressida.

**Cressida**
Discovery
Discovered by	Stephen P. Synnott / Voyager 2
Discovery date	January 9, 1986
Orbital characteristics
Mean orbit radius	61,766.730 ± 0.046 km^[2]
Eccentricity	0.00036 ± 0.00011^[2]
Orbital period	0.463569601 ± 0.000000013 d^[2]
Inclination	0.006 ± 0.040° (to Uranus' equator)^[2]
Satellite of	Uranus
Physical characteristics
Dimensions	92 × 74 × 74 km^[3]
Mean radius	41 ± 2 km^[3]
Surface area	~20,000 km²^[4]
Volume	~260,000 km³^[4]
Mass	~3.4×10¹⁷ kg^[4]
Mean density	~1.3 g/cm³ (assumed)
Equatorial surface gravity	~0.013 m/s²^[4]
Escape velocity	~0.034 km/s^[4]
Rotation period	synchronous^[3]
Axial tilt	zero^[3]
Albedo	0.08 ± 0.01^[5]
Temperature	~64 K^[4]

Image:Uranus-Portia-Cressida-Ophelia-NASA.gif

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Cressida (kres'-ə-də, IPA: /ˈkrɛsɨdə/) is an inner satellite of Uranus. It was discovered from the images taken by Voyager 2 on 1986-01-09, and was given the temporary designation S/1986 U 3.^[6] 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.^[7]

Cressida belongs to Portia Group of satellites, which also includes Bianca, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda and Perdita.^[5] These satellites have similar orbits and photometric properties.^[5] Unfortunately, other than its orbit,^[2] radius of 41 km^[3] and geometric albedo of 0.08^[5] 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.^[3] Its surface is grey in color.^[3]

References

^ [1]
^ ^a ^b ^c ^d ^e Jacobson, R.A. (1998). "The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager2 Observations". The Astronomical Journal 115: 1195-1199. doi:10.1086/300263.
^ ^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.
^ ^a ^b ^c ^d ^e ^f Calculated on the basis of other parameters
^ ^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.
^ Smith, B. A. (January 16, 1986). IAU Circular No. 4164. Retrieved on 2006-08-06.
^ Planet and Satellite Names and Discoverers. Gazetteer of Planetary Nomenclature. USGS Astrogeology (July 21, 2006). Retrieved on 2006-08-06.

External links

Cressida Profile by NASA's Solar System Exploration

v • d • e Uranus
Major Moons	Ariel · Miranda · Oberon · Titania · Umbriel
Characteristics	Atmosphere · Rings of Uranus · Moons
Discovery	William Herschel · William Lassell
Exploration	Voyager program · Voyager 2
Other	15 Orionis · Uranus-crosser asteroid · In fiction