Neso
A captured moon of Neptune about 60 km across, one orbit every 26.8 years, going the wrong way round.
Where it is right now
Neso is in Pisces, 29.0 AU away.
Computed for 2 August 2026, 17:00 UTC, and recomputed at least hourly. This page is cached, so treat the line above as accurate to the hour rather than to the second. The map shows the live position.
Position from a Kepler propagation of the published elements below, accurate to about an arcminute.
Facts
Every line carries the source it came from.
- Mean radius
- 30 kmSource: IAU/NASA planetary satellite fact sheets
- Orbits
- Neptune, 49,897,800 km out on averageSource: NASA/JPL Planetary Satellite Mean Elements
- Orbital period
- 26.8 yearsSource: NASA/JPL Planetary Satellite Mean Elements
- Orbit shape
- eccentricity 0.4550, inclined 128.40 degrees to the eclipticSource: NASA/JPL Planetary Satellite Mean Elements
- Discovered
- 2002 by M. Holman, J. Kavelaars, T. Grav, W. Fraser, D. MilisavljevicSource: NASA/JPL Planetary Satellite Discovery Circumstances
Physical size
- Mean radius
- 30.0 km
- Diameter
- 60 km across
Orbit
Elements are relative to Neptune.
- Average distance from Neptune
- 49.90 million km
- Closest and furthest
- 27.19 million km to 72.60 million km
- Eccentricity
- 0.4550, strongly elliptical
- Inclination to Neptune's reference plane
- 128.40 degrees
- Orbital period
- 26.8 years (9,805 days)
- Longitude of ascending node
- 55.40 degrees
- Argument of periapsis
- 89.80 degrees
- Mean anomaly at J2000.0
- 105.61 degrees
Family
Orbits Neptune.
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Catalog id neso. 3,172 objects on the map, of which 171 are hand-authored with sourced facts.