Nereid (moon)
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Image:Nereid-Voyager2.jpg Nereid (neer'-ee-əd [UK, US] or nair'-ee-əd [UK], IPA Template:IPA, Greek Νηρηΐδα), or Neptune II, is a moon of Neptune.
Nereid was discovered on 1 May 1949 by Gerard P. Kuiper. It is named after the Nereids, sea-nymphs of Greek mythology.
It was the outermost of Neptune's known moons for a long time (S/2002 N 1 through Psamathe have since taken that honour), and is the third largest, with a diameter of 340 km. Its orbit averages 5,513,400 km in radius, but is highly eccentric and varies from 1,353,600 to 9,623,700 kilometres. This is the most highly eccentric orbit of any known satellite in the solar system. The unusual Nereidian orbit suggests that it may be a captured asteroid or Kuiper belt object, or possibly that it was perturbed during the capture of Neptune's largest moon Triton. Very little else is known of Nereid.
Nereid was too far to be properly imaged by the Voyager 2 probe as it visited the Neptune system in 1989. Photos sent back show only its highly irregular shape as no surface features could be seen at the resolution available.
Data
- Orbital radius: 5,513,400 km
- Periposeidion: 1,353,600 km
- Apoposeidion: 9,623,700 km
- Diameter: 340 km
- Mass: 3.1Template:E kg
- Orbital period: 360.14 d
- Orbital inclination: 32.55° (to Neptune's equator), 7.232° (to the local Laplace plane), 5.07° (to the ecliptic)
- Rotation period: 0.48 d (11.52 h)
External links
| Image:Neptune symbol.png Neptune (satellites) edit |
|---|
| Naiad | Thalassa | Despina | Galatea | Larissa | Proteus | Triton | Nereid |
| S/2002 N 1 | S/2002 N 2 | S/2002 N 3 | Psamathe | S/2002 N 4 |
| See also: Pronunciation key | Rings of Neptune |
ca:Nereida (satèl·lit) da:Nereid de:Nereid (Mond) el:Νηρηίδα (δορυφόρος) es:Nereida (luna) fr:Néréide (lune) it:Nereide (astronomia) nl:Nereid (maan) pl:Nereida (księżyc) pt:Nereida (satélite) sk:Nereid (mesiac) zh:海卫二