Definition
Aphelion is the orbital point at maximum heliocentric distance. The distance at aphelion is a(1 + e). Highly eccentric orbits — such as that of Mars or Pluto — show a large difference between perihelion and aphelion distances.
Aphelion
The point in a solar orbit farthest from the Sun.
3D illustration
Aphelion markers highlight the farthest points from the Sun on each orbit.
Use the menu and time controls to explore. Based on Jean Meeus' Astronomical Algorithms.