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Neptune39S Natural Satellites

Neptune as seen by the Hubble Space Telescope , with four satellites, Proteus (top), Larissa (leftmost), Galatea (bottom right) and Despina (left of Neptune and the bottom right of Larissa).

Neptune has 13 moons, whose existence is confirmed, and 8 satellites Trojans ^Discoveries

Triton was first discovered on 10 October 1846 , just 17 days after the first observation of Neptune .

The second to be discovered Nereid was not until 1949 , more than a century after Triton.

Before the arrival of the probe Voyager 2 in the system of the planet, only Larissa was discovered (in 1981), in favor of an occultation of a star , this (third) moon could however be observed again before the overflight of Neptune by the spacecraft .

Analysis of photos transmitted by Voyager 2 in 1989 allowed to discover 5 new satellites: Naiad , Thalassa , Despina , Galatea and Proteus .

Halimeda , Sao , Laomdie and Neso (S/2002 N 1 through 4) were, as their temporary designation indicates, discovered during the same observing program in 2002. Psamathe (S/2003 N1), the last satellite discovered, was in 2003 .

List

Symbol
^{Prograde irregular satellites}	^{Retrograde irregular satellites}

Here is the list of known satellites of Neptune, ordered by the semi-major axis increase. The numerical values derived from data from the NASA.

Name		Designation Temporary	Dimensions (Km)	Mass (10 ¹⁶ kg)	Semi-major axis (Km)	Orbital period ( J )	Date Discovered
Neptune III	Naiad	S/1989 N 6	67 (96 60 52)	~ 19	48 227	0,294	1989
Neptune IV	Thalassa	S/1989 N 5	83 (108 100 52)	~ 35	50 075	0,311	1989
Neptune V	Despina	S/1989 N 3	152 (180 150 130)	~ 210	52 526	0,335	1989
Neptune VI	Galatea	S/1989 N 4	175 (204 184 144)	212	61 953	0,429	1989
Neptune VII	Larissa	S/1981 N 1 S/1989 N 2	195 (216 204 164)	~ 420	73 548	0,555	1981
Neptune VIII	Proteus	S/1989 N 1	418 (436 416 402)	~ 5000	117 647	1,122	1989
Neptune I	^Triton	-	2707	2 140 000	354 800	-5.877	1846
Neptune II	^Nereid	-	340	~ 3100	5 513 400	360,14	1949
Neptune IX	^Halimeda	S/2002 N 1	60	~ 9	15 728 000	-1879.71	2002
Neptune XI	^Sao	S/2002 N 2	38	~ 9	22 422 000	2914,07	2002
Neptune XII	^Laomdie	S/2002 N 3	38	~ 9	23 571 000	3167,85	2002
Neptune X	^Psamathe	S/2003 N 1	28	~ 1.5	46 695 000	-9115.91	2003
Neptune XIII	^Neso	S/2002 N 4	60	~ 9	48 387 000 (0.32 AU )	-9373.99	2002

Names

Triton has no official name until the ^twentieth century, although it was suggested in 1880 by Camille Flammarion and proposed independently by several other astronomers over the years ^, ^, , it was not used so common before the 1930s , Triton is known simply as "the satellite of Neptune" (the second satellite was not discovered until 1949).

Two asteroids share the same name as a satellite of Neptune (74) Galatea and (1162) Larissa.

The planet Neptune: information and data
W. Lassell, Lassell's Satellite of Neptune , Monthly Notices of the Royal Astronomical Society, Vol. 8, p. 8
GP Kuiper, The Second Satellite of Neptune , Publications Of The Astronomical Society of the Pacific, Vol. 61, No. 361, p. 175
Reitsema HJ, WB Hubbard, LA Lebofsky and DJ Tholen, Science, vol. 215, pp. 289-291
^{a , b and c} IAUC 4824: Sats OF NEPTUNE, 1989M, PU Vul, V482 Cyg
^{a and b} IAUC 4867: NEPTUNE, JUPITER
IAUC 3608: 1981 N 1; Sats OF SATURN; 1980l
^{a , b and c} MPEC 2003-A75: S/2002 N 1, 2002 No. 2, 2002 N3
MPEC 2003-S107: S/2002 N 4
MPEC 2003-A19: S/2003 N 1
^{a , b , c and d} A revolution period indicates a negative orbit retrograde
EW Maunder , An Indian mode of informal & informal time , The Observatory, Vol. 28 (1905), p. 468
WT Lynn, Perihelion distance of Halley's Comet , The Observatory, Vol. 29 (1906), pp. 67-68
JB Snell Names of Satellites , The Observatory, Vol. 32 (1909), pp. 295-297
SB Nicholson, The Satellites of Jupiter , Publications Of The Astronomical Society of the Pacific, Vol. 31, No. 300 (1939), p. 85

Neptune's natural satellites
Naiad Thalassa Despina Galatea Larissa Proteus Triton Nereid Halimeda Sao Laomdie Psamathe Neso
See also: Neptune Rings of Neptune

The Solar System

Sun Mercury Venus Earth March Ceres Jupiter Saturn Uranus Neptune Pluto Haumea Makemake Eris
Massive objects in the Kuiper Belt	Sedna Quaoar (225088) 2007 OR ₁₀ Charon (84522) 2002 TC ₃₀₂ Orcus Varuna 2007 UK126 2005 QU182
Moons and asteroid moons	Mercurial Venusian Land : Moon Martian Jovian : Io Europe Ganymede Callisto Saturn : Titan Uranian Neptunian : Triton Plutonniennes Haumeainnes Erisians
Rings	Jovian Saturniens Uranians Neptunian Plutonian Ganymede Callisto Europe Rhea
Small bodies	Asteroids ( list ): Pallas Juno Vesta Comets : 1P/Halley 2P/Encke Damocloids Meteoroids
Main areas	Vulcanoids Belt asteroids Centaurus Kuiper belt Scattered disc objects Objects detached Hills Cloud Oort Cloud
Other	Heliosphere Heliopause heliosheath Formation and evolution of the solar system Interplanetary medium Hypothetical Planets C/1992 J1
List of solar system objects sorted by: size mass distance from the Sun