Ophelia (moon)

There is also an asteroid called 171 Ophelia.

Ophelia

Discovery image of Ophelia (top of image, outside of rings)
Discovery
Discovered by	Richard J. Terrile / Voyager 2
Discovery date	January 20, 1986
Orbital characteristics
Mean orbit radius	53,763.390 ± 0.847 km[1]
Eccentricity	0.00992 ± 0.000107[1]
Orbital period	0.37640039 ± 0.00000357 d[1]
Inclination	0.10362 ± 0.055° (to Uranus' equator)[1]
Satellite of	Uranus
Proper orbital elements
Physical characteristics
Dimensions	54 × 38 × 38 km[2]
Mean radius	21.4 ± 4 km[2][3][4]
Surface area	~6600 km²[a]
Volume	~41,000 km³[a]
Mass	~5.3×1016 kg[a]
Mean density	~1.3 g/cm³ (assumed)[3]
Equatorial surface gravity	~0.0070 m/s²[a]
Escape velocity	~0.018 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]

Ophelia ( /ɵˈfiːliə/ o-fee-lee-ə) is a 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 8.^[6] It was not seen until the Hubble Space Telescope recovered it in 2003.^[5][7] Ophelia was named after the daughter of Polonius, Ophelia, in William Shakespeare's play Hamlet. It is also designated Uranus VII.^[8]

Other than its orbit,^[1] radius of 21 km^[2] and geometric albedo of 0.08^[5] virtually nothing is known about it. At the Voyager 2 images Ophelia appears as an elongated object, the major axis pointing towards Uranus. The ratio of axes of the Ophelia's prolate spheroid is 0.7 ± 0.3.^[2]

Ophelia acts as the outer shepherd satellite for Uranus' Epsilon ring.^[9] The orbit of Ophelia is within the synchronous orbit radius of Uranus, and therefore the moon is slowly decaying due to tidal forces.^[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, E. (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

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