Neptune is the eighth and last planet, the most distant solar system to 4.498 253 billion km.
Reaches of our solar system we find Neptune, the planet gas giant and ice, almost 4 times larger than Earth with a diameter of 49 922 km.
Neptune orbits the Sun in 164 years 323 days 21.7 hours and the day is 16H 6.6 min.
Its atmosphere is windswept fastest in the solar system (up to 1600 km/h) but its winds of hydrogen, helium and methane are so light they would not turn a land wind. However, giant storms developed there.
The moons of Neptune system is complex, some moons may be of extra-solar. Indeed Neptune's moons to draw from the material beyond the orbit of Pluto, probably in the Kuiper Belt where many objects revolve. Occasionally objects collide and are projected through the solar system, some of these icy bodies are transformed into comets but others may be attracted by a giant planet and become one of its moons.
This is what scientists envision for Triton.
The orbit of Triton reversed relative to the rotation of Neptune and its characteristics suggest it belonged to the Kuiper belt and it is not an isolated case.
For example, the outer moons of Jupiter, Ananke, Carme, Pasiphae and Sinope and those of Saturn, Phoebe also have a retrograde orbit, but all are less than 10% of the diameter of Triton.
Triton's largest moon of Neptune, is the coldest object (-198°C) in the Solar System, colder than Pluto which it resembles.
At this temperature the nitrogen should be in a gaseous state, it forms a golden dome ice at both poles of the moon. Its surface reflects approximately 70% of the light as it absorbs little light it is very cold.
Plumes cryovolcanism on its surface, captured by the Voyager spacecraft, are fascinating, they spit a mixture of liquid nitrogen, methane and ammonia.
The probe shows a complex and active.
The dark streaks on the picture cons seem to come from small volcanoes and consist of nitrogen frost mixed with organic compounds ejected by geysers of Triton.
In the light atmosphere of Triton, these eruptions immediately freeze and ice falls of snow. Traveling with the first quick overview of Triton gave us much information but not enough for scientists.
Triton is a moon very interesting because it can potentially contain water and thus traces of life.
- Naiad (N III Naiad) is the closest moon of Neptune, discovered in 1989 by Voyager 2.
- Thalassa (N IV Thalassa) is the second moon of Neptune, discovered in 1989 by Voyager 2.
- Despina (NV Despina) is the third moon of Neptune, discovered in 1989 by Voyager 2.
- Galatea (Galatea VI N) is the fourth moon of Neptune, discovered in 1989 by Voyager 2.
- Larissa (Larissa N VII) is the fifth moon of Neptune, discovered by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky and David J. Tholen at a star occultation by Neptune May 24, 1981.
- Proteus (Proteus VIII N) is the sixth moon of Neptune, discovered in 1989 by Stephen P. Synnott and Bradford A. Smith.
- Triton (Triton NI) is the seventh and largest moon of Neptune, discovered in 1846, just 17 days after Neptune by William Lassell.
- Nereid (N II Nereid) is the eighth moon of Neptune, discovered in 1949 by Gerard Kuiper.
- Halimeda is the ninth moon of Neptune, discovered in 2002 by the team of Matthew J. Holman.
- Sao is the tenth moon of Neptune, discovered in 2002 by the team of Matthew J. Holman.
- Laomedeia is the eleventh moon of Neptune, discovered in 2002 by the team of Matthew J. Holman.
- Psamathe is the twelfth moon of Neptune, discovered by the team of Scott S. Sheppard.
- Neso is the thirteenth moon of Neptune and the later discovered by the team of Matthew J. Holman.
- S/2004 N 1 is the fourteenth moon of Neptune, which orbits the planet in a little less than one earth day.
Moons of Neptune |
diameter (km) |
Semi-major axis (km) |
Triton | ≈2 706 | 354 759 |
Proteus | ≈420 | 117 646 |
Nereid | ≈340 | 5 513 818 |
Larissa | ≈194 | 73 548 |
Galatea | ≈176 | 61 953 |
Despina | ≈150 | 52 526 |
Thalassa | ≈82 | 50 074 |
Naiad | ≈66 | 48 227 |
Halimede | ≈62 | 16 611 000 |
Neso | ≈60 | 49 285 000 |
Sao | ≈44 | 22 228 000 |
Laomedia | ≈42 | 23 567 000 |
Psamathe | ≈40 | 48 096 000 |
S/2004 N1 | ≈18 | 105 283 |