# How far away is the sun from neptune in AU?

There is a notion that the average of perihelion and aphelion ( semi-major axis a) is the average distance, over one period of revolution. Actually, in mathematical exactitude, the average distance for an orbiter is semi-minor axis b = asqrt( 1 $-$ e^2 ), of the orbit. For Neptune, the eccentricity is 0.011257 and b = 4494.8 M km= 30.046 AU against a =30.052 AU.,