SMALL OUTER SATELLITES OF NEPTUNE :

S/2002 N1 (N-9), N2 (N-11), N3 (N-12), N4 (N-13), S/2003 N1 (N-10)

Credit : IFA-Hawaï/Subaru

Above a picture of the satellite S/2003 N1 discovered on August 29, 2003 at the 8m-telescope "Subaru" on the island of Hawaii. Neptune is not on the image but half a degree West.

Satellite S/2002 N1 3 were discovered 4m telescope"Blanco" of Cerro Tololo at Chile. They were confirmed with 8m "VLT" at Paranal, the 2,6m "Nordic Optical Telescope" and 5m Mount Palomar.

These satellites, very faint and very slow, are difficult to detect and it takes a long time to determine a good orbit.

	Semi-major axis in km (a)	Eccentricity of the orbit (e)	Inclination on the ecliptic (i)	Revolution period	Diameter
S/2002 N1 N-9 Halimede	16 810 649	0.2604	112°	5.13 years	61 km
S/2002 N2 N-11 Sao	22 242 050	0.1409	52°	6.89 years	40 km
S/2002 N3 N-12 Laomedeia	23 512 382	0.3929	37°	7.92 years	40 km
S/2002 N4 N-13 Neso	49 035 895	0.6312	140°	24.41 years	38 km
S/2003 N1 N-10 Psamathe	47 463 273	0.2328	124°	26.34 years	60 km

a, e et i: average on 10 years from 2006 to 2016

For more on the orbital parameters of the satellites, click here.