Portia (moon)
 |
|
| Discovery | |
|---|---|
| Discovered by | Stephen P. Synnott / Voyager 2 |
| Discovery date | January 3, 1986 |
| Orbital characteristics | |
| 66,097.265 ± 0.050 km | |
| Eccentricity | 0.00005 ± 0.00008 |
| 0.5131959201 ± 0.0000000093 d | |
|
Average orbital speed
|
9.37 km/s |
| Inclination | 0.05908 ± 0.039° (to Uranus' equator) |
| Satellite of | Uranus |
| Physical characteristics | |
| Dimensions | 156 × 126 × 126 km |
|
Mean radius
|
67.6 ± 4 km |
| ~57,000 km² | |
| Volume | ~1,300,000 km³ |
| Mass | ~1.7×1018kg |
|
Mean density
|
~1.3 g/cm³ (assumed) |
| ~0.023 m/s2 | |
| ~0.058 km/s | |
| synchronous | |
| zero | |
| Albedo |
|
| Temperature | ~64 K |
Portia (/ˈpɔːrʃə/ POR-shə) is an inner satellite of Uranus. It was discovered from the images taken by Voyager 2 on 3 January 1986, and was given the temporary designation S/1986 U 1. The moon is named after Portia, the heroine of William Shakespeare's play The Merchant of Venice. It is also designated Uranus XII.
Portia is the second-largest inner satellite of Uranus after Puck. The Portian orbit, which lies inside Uranus' synchronous orbital radius, is slowly decaying due to tidal deceleration. The moon will one day either break up into a planetary ring or hit Uranus.
It heads a group of satellites called the Portia Group, which includes Bianca, Cressida, Desdemona, Juliet, Rosalind, Cupid, Belinda and Perdita. These satellites have similar orbits and photometric properties.
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