During 1845-'46, Urban Le Verrier insisted through his mathematical
calculations that there ought to be a solar planet orbiting Sun,
beyond Uranus that as discovered by William Herschel in 1781.
The mean radius from Sun to Neptune is about 30.05 AU
The small eccentricity of the elliptic but nearly circular orbitis 0 -0112.
The orbit period is nearly 164.79 Earth years.
Blue-hued, it is dark, due to lesser insolation.
Atmosphere comprises mostly nitrogen.
Without rigid surface, the temperature therein ls less than
Understandably, day/night spin is differential, with equator day +
night = 15 h 57 m 59 s..
Equatorial size is 3.88 X Earth's.
Moons 13, 5 of which were discovered in this century only.
The three icy ring systems are Galle, Verrier and Adams..
For more data, see NASA Planetary facts data.