Psamathe , also known as Neptune X, is a retrograde irregular satellite of Neptune. It is named after

Psamathe Psamathe may refer to: Greek mythology * Psamathe (Nereid) * Psamathe (Crotopus), Daughter of Crotopus Other * Psamathe (moon), moon of Neptune * ''Psamathe'' (polychaete), polychaete Polychaeta () is a paraphyletic class of generally marine ...

, one of the

Nereid In Greek mythology, the Nereids or Nereides ( ; grc, Νηρηΐδες, Nērēḯdes; , also Νημερτές) are sea nymphs (female spirits of sea waters), the 50 daughters of the ' Old Man of the Sea' Nereus and the Oceanid Doris, sisters ...

s. Psamathe was discovered by Scott S. Sheppard and

David C. Jewitt David Clifford Jewitt (born 1958) is a British-American astronomer who studies the Solar System, especially its minor bodies. He is based at the University of California, Los Angeles, where he is a Member of the Institute for Geophysics and Pl ...

in 2003 using the 8.2 meter

Subaru telescope is the telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades. It had the largest monolithic primary mirror in t ...

. Before the announcement of its name on February 3, 2007 (IAUC 8802), it was known by the

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calc ...

S/2003 N 1. Psamathe is about 38 kilometers in diameter. It orbits Neptune at a distance of between 25.7 and 67.7 million km (for comparison, the Sun- Mercury distance varies between 46 million and 69.8 million km) and requires almost 25 Earth years to make one orbit. The orbit of this satellite is close to the theoretical stable separation from Neptune for a body in a retrograde orbit. Given the similarity of Psamathe's orbital parameters with Neso (S/2002 N 4), it was suggested that both irregular satellites could have a common origin in the break-up of a larger moon. Both are further from their primary than any other known moon in the Solar System.

References

External links

Neptune's Known Satellites
(by Scott S. Sheppard)
S/2003 N1 Neptune Satellite Movie Images
(image)

Mean orbital parameters (NASA)

{{Neptune Moons of Neptune Irregular satellites Discoveries by Scott S. Sheppard Astronomical objects discovered in 2003 Moons with a retrograde orbit

See also

References

External links