The disappearing moon of Neptune

A team of American astronomers discovers what they believe is a third moon of Neptune from ground-based telescope observations, but S/1981N1 isn’t seen again for several years, so the discovery is left in the “unconfirmed” category…until it is next seen by Voyager 2 in 1989, confirming the original sighting many years later. In 1991, the International Astronomical Union will name this moon Larissa. (Voyager 2 photo of Larissa shown)