use names ending in "a" for prograde satellites, names ending in "e" for retrograde satellites, and names ending in "o" for exceptionally inclined satellites, exactly like the convention for the moons of Jupiter. Two asteroids share the same names as moons of Neptune: 74 Galatea and 1162 Larissa. Characteristics The moons of Neptune can be divided into two groups: regular and irregular. The first group includes the seven inner moons, which follow circular prograde orbits lying in the equatorial plane of Neptune. The second group consists of all seven other moons including Triton. They generally follow inclined eccentric and often retrograde orbits far from Neptune; the only exception is Triton, which orbits close to the planet following a circular orbit, though retrograde and inclined. Regular moons In order of distance from Neptune, the regular moons are Naiad, Thalassa, Despina, Galatea, Larissa, Hippocamp, and Proteus. All but the outer two are within Neptune-synchronous orbit (Neptune's rotational period is 0.6713 day or 16 hours) and thus are being tidally decelerated. Naiad, the closest regular moon, is also the second smallest among the inner moons (following the discovery of Hippocamp), whereas Proteus is the largest regular moon and the second largest moon of Neptune. The first five moons orbit much faster than Neptune's rotation itself ranging from 7 hours for Naiad and Thalassa, to 13 hours for Larissa. The inner moons are closely associated with Neptune's rings. The two innermost satellites, Naiad and Thalassa, orbit between the Galle and LeVerrier rings. Despina may be a shepherd moon of the LeVerrier ring, because its orbit lies just inside this ring. The next moon, Galatea, orbits just inside the most prominent of Neptune's rings, the Adams ring. This ring is very narrow, with a width not exceeding 50 km, and has five embedded bright arcs. The gravity of Galatea helps confine the ring particles within a limited region in the radial direction, maintaining the narrow ring. Various resonances between the ring particles and Galatea may also have a role in maintaining the arcs. Only the two largest regular moons have been imaged with a resolution sufficient to discern their shapes and surface features. Larissa, about 200 km in diameter, is elongated. Proteus is not significantly elongated, but not fully spherical either: it resembles an irregular polyhedron, with several flat or slightly concave facets 150 to 250 km in diameter. At about 400 km in diameter,