Psamathe was discovered by Scott S. Sheppard, David C. Jewitt and Jan T. Kleyna Aug. 29, 2003 using the 8.3-m Subaru reflector at the Mauna Kea Observatory on the island of Hawaii.
Psamathe is so distant from Neptune it takes almost 26 Earth years to make a single orbit around the ice giant. The moon's orbit is among the most distant from its planet than any other known moon in our solar system.
The small moon shares similar orbital parameters with with another moon of Neptune―Neso. Both Psamathe and Neso may be fragments from the break-up of a larger moon billions of years ago.
How Psamathe Got its Name
Psamathe like many of the satellites of Neptune, is named after one of the Nereids. Psamathe was originally designated S/2003 N 1.