Neptune

Neptune is the 8th planet in the Solar System.

Orbital Parameters

Mean Distance from Sun 4,496.7 million km

30.058 AU

Maximum Distance from Sun 4,537 million km

30.316 AU

Minimum Distance from Sun 4,456 million km

29.800 AU

Sidereal Period (year) 164.8 Earth-years

60,190.3 Earth-days

Synodic Period 367.5 Earth-days
Rotational Period (day) 16h 3m Earth-time
Mean Orbital Velocity 5.43 km/sec
Orbital Inclination 1º 45' 19.8"
Orbital eccentricity 0.009
Axial inclination 28º 48'

Physical Parameters

Equatorial Diameter 50,538 kilometres
Polar Diameter 49,600 kilometres
Apparent diameter as seen from Earth Max 2.2"

Min 2.0"
Oblateness 0.02
Mass 17.2 x Earth
Reciprocal Mass (Sun = 1) 19,300
Volume 57 x Earth
Density 2.06 x (the density of water)

Some authorities put this figure as 1.77
Surface Gravity 1.2 x Earth
Escape Velocity 23.9 kilometres per second
Albedo 0.35
Maximum magnitude +7.7 Binoculars are required to see Neptune
Mean cloudtop temperature -220ºC
Mean diameter of the Sun as seen from Neptune 1' 04"

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