Cordelia (moon)

Cordelia

Cordelia (lower-middle, inside of bright ring), discovery image from Voyager 2
Discovery
Discovered by	Richard J. Terrile / Voyager 2
Discovery date	January 20, 1986
Orbital characteristics
Mean orbit radius	49751.722 ± 0.149 km[1]
Eccentricity	0.00026 ± 0.000096[1]
Orbital period	0.33503384 ± 0.00000058 d[1]
Inclination	0.08479 ± 0.031° (to Uranus' equator)[1]
Satellite of	Uranus
Proper orbital elements
Physical characteristics
Dimensions	50 × 36 × 36 km[2]
Mean radius	20.1 ± 3 km[2][3][4]
Surface area	~5500 km²[a]
Volume	~38,900 km³[a]
Mass	~4.4×1016 kg[a]
Mean density	~1.3 g/cm³ (assumed)[3]
Equatorial surface gravity	~0.0073 m/s²[a]
Escape velocity	~0.017 km/s[a]
Rotation period	synchronous[2]
Axial tilt	zero[2]
Albedo	0.08 ± 0.01 [5] 0.07[3][4]
Temperature	~64 K[a]

Cordelia ( /kɔrˈdiːliə/ kor-dee-lee-ə) is the innermost moon of Uranus. It was discovered from the images taken by Voyager 2 on January 20, 1986, and was given the temporary designation S/1986 U 7.^[6] It was not detected again until the Hubble Space Telescope observed it in 1997.^[5][7] Cordelia takes its name from the youngest daughter of Lear in William Shakespeare's King Lear. It is also designated Uranus VI.^[8]

Other than its orbit,^[1] radius of 20 km^[2] and geometric albedo of 0.08^[5] virtually nothing is known about it. At the Voyager 2 images Cordelia appears as an elongated object, the major axis pointing towards Uranus. The ratio of axes of the Cordelia's prolate spheroid is 0.7 ± 0.2.^[2]

Cordelia acts as the inner shepherd satellite for Uranus' Epsilon ring.^[9] Cordelia's orbit is within Uranus' synchronous orbit radius, and is therefore slowly decaying due to tidal deceleration.^[2]

See also

• Moons of Uranus

References

Explanatory notes

1. ^ ^{a b c d e f} Calculated on the basis of other parameters.

Citations

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 (3): 1195–1199. Bibcode 1998AJ....115.1195J. doi:10.1086/300263.  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 (1): 69–77. Bibcode 2001Icar..151...69K. doi:10.1006/icar.2001.6597.  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} 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.  edit
6. ^ Smith, B. A. (1986-01-27). "Satellites and Rings of Uranus". IAU Circular 4168. http://www.cbat.eps.harvard.edu/iauc/04100/04168.html#item1. Retrieved 2011-10-31. 
7. ^ Showalter, M. R.; Lissauer, J. J. (2003-09-03). "Satellites of Uranus". IAU Circular 8194. http://www.cbat.eps.harvard.edu/iauc/08100/08194.html. Retrieved 2011-10-31. 
8. ^ "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. July 21, 2006. http://planetarynames.wr.usgs.gov/append7.html. Retrieved 6 August 2006. 
9. ^ Esposito, L. W. (2002). "Planetary rings". Reports On Progress In Physics 65 (12): 1741–1783. Bibcode 2002RPPh...65.1741E. doi:10.1088/0034-4885/65/12/201.  edit

External links

• Cordelia Profile by NASA's Solar System Exploration
• Uranus' Known Satellites (by Scott S. Sheppard)