Most distant moon from a planet

Neso, the 13th moon of Neptune to be discovered, was first observed on 14 August 2002 but was not recognized as a moon of Neptune until the following year. It orbits the planet at an average distance of 50,183,000 km from Neptune's center, taking 9,631.9 days (26.37 Earth years) to complete one orbit. Its orbit is quite elliptical; at its apoapsis, it reaches a distance of 70,225,000 km from Neptune's center. It orbits Neptune retrograde, or "backwards" from Neptune's motion around the Sun, indicating that it is likely a captured object that began its existence as an icy world beyond Neptune.

Neso's semimajor axis is 50,183,000 km and its orbit eccentricity is 0.40.