PORTIA (MOON)

'Portia' ''(por'-shə,'' ) is an inner satellite of Uranus. It was discovered from the images taken by ''Voyager 2'' on 1986-01-03, and was given the temporary designation 'S/1986 U 1'.^[3] The moon is named after Portia, the heroine of William Shakespeare's play ''The Merchant of Venice''. It is also designated 'Uranus XII'.^[4]
Portia is the second largest inner satellite of Uranus after Puck. The Portian orbit lies inside Uranus' synchronous orbital radius and is slowly decaying due to tidal deceleration and will one day either break up into a planetary ring or impact on Uranus' surface. Portia heads a group of satellites called 'Portia Group', which also includes Bianca, Cressida, Desdemona, Juliet, Rosalind, Cupid, Belinda and Perdita. These satellites have similar orbits and photometric properties. Unfortunately, other than its size of about 140 km, orbit and geometric albedo of approximately 0.08 virtually nothing is known about Portia.
At the Voyager 2 images Portia appears as an elongated object, the major axis pointing towards Uranus. The ratio of axises of the Portia's prolate spheroid is 0.8 ± 0.1. Its surface is grey in color. Observations with Hubble Space Telescope and large terrestial telescopes found water ice absorption features in the spectrum of Portia. Hubble Space Telescope NICMOS Multiband Photometry of Proteus and Puck, , Christophe, Dumas, Astronomical Journal, 2003

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References

1. Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites, , Erich, Karkoschka, Icarus, 2001
2. Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope, , Erich, Karkoschka, Icarus, 2001
3. IAU Circular No. 4164
4. Planet and Satellite Names and Discoverers

External links

Portia Profile by NASA's Solar System Exploration