10th Largest Moon of Neptune - Neso (13th Moon outwards from Neptune)

Neso, is the outermost irregular retrograde natural satellite of Neptune.

Neso is the 10th overall largest satellite of Neptune and 62th largest moon in the Solar System currently known.

Discovery

Matthew J. Holman, Harvard-Smithsonian Center for Astrophysics (CfA); John J. Kavelaars, National Research Council of Canada; T. Grav, University of Oslo and CfA; and W. Fraser and Dan Milisavljevic, McMaster University, reported the discovery of three satellites of Neptune on CCD images obtained in 14 August 2002 with the 4-m Blanco telescope at Cerro Tololo.

Naming

The moon was given the temporary designation S/2002 N4.

Neso the moon is named after one of the Nereids, the fifty daughters of Nereus and Doris.

Stats

Diameter (mean): 60 km

Semi-major axis: 49,285,000 km

Orbital Period: -9740.73 days

Rotation Period: ?

Orbit

Neso orbits Neptune at a distance of more than 48 Gm (million km), making it the most distant known moon of any planet. It follows a highly inclined and highly eccentric orbit.

Formation

Given the similarity of the orbit's parameters with the next inner satellite, Psamathe, it was suggested that both irregular satellites could have a common origin in the break-up of a larger moon.

Physical characteristics

Little is known about Neso.

Neso is about 60 kilometers in diameter (assuming an albedo of 0.04).