From July to September 1989, Voyager 2 discovered six moons of Neptune. Of these, the irregularly shaped Proteus is notable for being as large as a body of its density can be without being pulled into a spherical shape by its own gravity. Although the second-most-massive Neptunian moon, it is only 0.25% the mass of Triton. Neptune's innermost four moons—Naiad, Thalassa, Despina and Galatea—orbit close enough to be within Neptune's rings. The next-farthest out, Larissa, was originally discovered in 1981 when it had occulted a star. This occultation had been attributed to ring arcs, but when Voyager 2 observed Neptune in 1989, Larissa was found to have caused it. Five new irregular moons discovered between 2002 and 2003 were announced in 2004. A new moon and the smallest yet, S/2004 N 1, was found in 2013. Because Neptune was the Roman god of the sea, Neptune's moons have been named after lesser sea gods.
From July to September 1989 , Voyager 2 discovered six moons of Neptune . Of these , the irregularly shaped Proteus is notable for being as large as a body of its density can be without being pulled into a spherical shape by its own gravity . Although the second - most - massive Neptunian moon , it is only 0.25 % the mass of Triton . Neptune 's innermost four moons — Naiad , Thalassa , Despina and Galatea — orbit close enough to be within Neptune 's rings . The next - farthest out , Larissa , was originally discovered in 1981 when it had occulted a star . This occultation had been attributed to ring arcs , but when Voyager 2 observed Neptune in 1989 , Larissa was found to have caused it . Five new irregular moons discovered between 2002 and 2003 were announced in 2004 . A new moon and the smallest yet , S/2004 N 1 , was found in 2013 . Because Neptune was the Roman god of the sea , Neptune 's moons have been named after lesser sea gods .
When was Neptune's moon Larissa discovered?
When was Neptune 's moon Larissa discovered ?
1981
1981