The Moons of Neptune


Triton,
in Greek mythology the son of Poseidon, is the largest of Neptune's  fourteen confirmed natural satellites and with a diameter of 2,700 kilometers is almost the size of Luna the moon of Earth. It has a tenuous almost non-existent atmosphere composed mainly of nitrogen and methane and a surface temperature of -240 Celsius, but because it is geologically active (its surface is covered in ice volcanoes) there is a possibility of aquatic life existing beneath its frozen exterior.

Triton is unique amongst large moons in that it's in a retrograde orbit with its primary (it orbits in a direction opposite to the planet's rotation), but tidal interactions are slowly causing the orbit's decay, and predictions are that some 3.6 billion years from now the moon will pass Neptune's Roche limit [1] disintegrate and form a ring system similar to Saturn's.

The 13 minor moons, being small, lack the mass/self-gravity necessary to assume a spherical shape:

Proteus is irregularly shaped and with a diameter of 418 km is the second largest of Neptune's satellites.
Nereid is irregularly shaped, has a diameter of 340 km and is possibly a captured asteroid or Kuiper belt object.
Larissa is irregularly shaped and has a diameter of 193 km.
Galatea is irregularly shaped and has a diameter of 158 km.
Despina is irregularly shaped and has a diameter of 148 km.
Thalassa is irregularly shaped and has a diameter of 80 km.
Naiad is irregularly shaped and has a diameter of 58 km.
Halimede is irregularly shaped and has a diameter of 62 km.
Sao is irregularly shaped and has a diameter of 44 km.
Laomedeia is irregularly shaped and has a diameter of 42 km.
Neso is irregularly shaped, has a diameter of 60 km and with an orbit of 48 million killometers is the outermost of Neptune's satellites.
Psamathe is irregularly shaped and with a diameter of only 38 killometers the second smallest. It and Neso are further from their primary than any other moons in the Solar System and are suspected to have been, at one time, part of a larger common object.
S/2004 N 1 (provisional) the latest and smallest of Neptune's moons was discovered accidentally by Mark Showalter an astronomer at the SETI Institute while perusing old Hubble images. The moon is 20 km (12 miles) in diameter (so small and faint Voyager 2 failed to spot it while surveying the Neptunian system in 1989). The newly found satellite is located between Larissa and Proteus.


[1] The Roche limit/radius is the minimum distance at which a small celestial body can orbit a second more massive celestial body (usually a satellite and its primary) before being torn apart by tidal forces.





To Site Map
Copyright
2006-2017  factfictionandconjecture.ca   All rights reserved