Sycorax (moon)

Sycorax "(sik'-or-aks," IPAEng|ˈsɪkɔræks) is the largest retrograde irregular satellite of Uranus.Sycorax was discovered on 1997-09-06 by Brett J. Gladman, Philip D. Nicholson, Joseph A. Burns, and John J. Kavelaars using the 200-inch Hale telescope, together with Caliban and given the temporary designation S/1997 U 2.GLADMAN, NICHOLSON, BURNS, KAVELAARS, MARSDEN, WILLIAMS & OFFUTT"Discovery of two distant irregular moons of Uranus", Nature, 392 (1998), pp. 897 - 899]

Officially confirmed as Uranus XVII, it was named after Sycorax, Caliban's mother in William Shakespeare's play "The Tempest".

Orbit

Sycorax follows a distant orbit, more than 20 times further from Uranus than the furthest regular moon Oberon. Its orbit is retrograde, moderately inclined and eccentric.The orbital parameters suggest that it may belong, together with Setebos and Prospero, to the same dynamic cluster, suggesting common origin.Grav, Tommy; Holman, Matthew J.; Gladman, Brett J.; Aksnes, Kaare"Photometric survey of the irregular satellites",Icarus, 166,(2003), pp. 33-45. [http://arxiv.org/abs/astro-ph/0301016 Preprint] ] The diagram illustrates the orbital parameters of the retrograde irregular satellites of Uranus (in polar co-ordinates) with the eccentricity of the orbits represented by the segments extending from the pericentre to the apocentre.

Physical characteristics

The diameter of Sycorax is estimated at 150 km (assuming albedo of 0.04) making it the largest irregular satellite of Uranus, comparable in size with Himalia, the biggest irregular satellite of Jupiter.

The satellite appears "light-red" (colour indices B-V=0.87 V-R=0.44,cite journal | last=Maris | first=Michele | coauthors=Giovanni Carraro, Gabrielle Cremonese, Marco Fulle | year=2001 | month=May | title=Multicolor Photometry of the Uranus Irregular Satellites Sycorax and Caliban | journal=The Astronomical Journal | volume=121 |issue=5 | pages=2800–2803 | url=http://www.iop.org/EJ/article/1538-3881/121/5/2800/200443.html | accessdate= 2008-09-14 | doi=10.1086/320378 ] ) redder than Himalia but still less red than most Kuiper Belt Objects.

The rotation period could not be estimated conclusively (best fit ~4 h).

ee also

*Uranus' natural satellites
*irregular satellites

References

External links

* [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Ura_Sycorax Sycorax Profile] (by [http://solarsystem.nasa.gov NASA's Solar System Exploration] )
* [http://www.ifa.hawaii.edu/~jewitt/irregulars.html David Jewitt pages]
* [http://www.dtm.ciw.edu/sheppard/satellites/urasatdata.html Uranus' Known Satellites] (by Scott S. Sheppard)
* [http://cfa-www.harvard.edu/iau/NatSats/NaturalSatellites.html Ephemeris IAU-NSES]