The four remaining, unnamed outer satellites of Neptune now have official names. S/ 2002 N 1 is now Halimede, S/ 2002 N 2 is now Sao, S/ 2002 N 3 is now Laomedeia, and S/ 2002 N 4 is now Neso.
Neso is unique as the most distantly orbiting satellite from any planet, with a semimajor axis of 48,387,000 km, or 0.32 au. With its eccentric orbit, it actually reaches farther away from Neptune than Mercury gets from the Sun. Also of note is Sao. While all these moons are technically named after Nereides, SAO is the acronym for the Smithsonian Astrophysical Observatory, at the Harvard-Smithsonian Center for Astrophysics, discoverer Matthew Holman's home institution