Naiad is the innermost satellite of Neptune, named after the Naiads of Greek legend. Naiad is irregularly shaped and probably has not been modified by any internal geological processes since its formation. It is likely that it is a rubble pile re-accreted from fragments of Neptune's original satellites, which were smashed up by perturbations from Triton soon after that moon's capture into a very eccentric initial orbit. Naiad orbits about 23,500 km above Neptune's cloud tops. Since this is below the synchronous orbit radius, its orbit is slowly decaying due to tidal deceleration and it may eventually impact Neptune's atmosphere, or break up into a planetary ring upon passing its Roche limit due to tidal stretching.
Naiad (moon) - Wikipedia, the free encyclopedia