 Sao imaged by theVery Large Telescope's FORS1 imager in September 2002 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | |
| Discovery date | August 14, 2002 |
| Designations | |
Designation | Neptune XI |
| Pronunciation | /ˈseɪ.oʊ/ |
Named after | ΣαώSaō |
| S/2002 N 2 | |
| Adjectives | Saonian/seɪˈoʊniən/[3] |
| Orbital characteristics[4] | |
| Epoch June 10, 2003 | |
| 22,228,000 km | |
| Eccentricity | 0.1365 |
| 2912.72 days (7.97yr) | |
| Inclination | 53.483° |
| Satellite of | Neptune |
| Group | Sao group |
| Physical characteristics | |
| 44 km(for albedo 0.04)[5] | |
| Albedo | 0.04(assumed)[5] |
Sao/ˈseɪ.oʊ/ is aprogradeirregular satellite ofNeptune. It was discovered byMatthew J. Holmanet al. on August 14, 2002.[6]
Sao orbits Neptune at a distance of about 22.4 million km and is about 44 kilometers in diameter (assuming analbedo of 0.04).[5]
Sao follows an exceptionallyinclined and moderatelyeccentric orbit illustrated on the diagram in relation to other irregular satellites of Neptune. The satellites above the horizontal axis areprograde, the satellites beneath it are retrograde. The yellow segments extend from thepericentre to theapocentre, showing the eccentricity.
The satellite is inKozai resonance, i.e. its inclination and eccentricity are coupled (the inclination of the orbit decreases while eccentricity increases andvice versa).[6]
Sao, orNeptune XI, like many of the outer satellites of Neptune, is named after one of theNereids;Sao was associated with sailing and is referred to as "The rescuer" or "Safety". Before the announcement of its name on February 3, 2007 (IAUC 8802), Sao was known provisionally as S/2002 N 2.
Listed in approximately increasing distance fromNeptune | |||||||||||
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