The figure shows the elliptical orbit of a celestial object around the Sun (yellow circle). At the point which is marked with a red dot, the distance to the Sun is greatest, it is designated as the aphelion of the orbit. The aphelion distance is marked with a fat blue line. The other thin blue lines, which are drawn with time differences of 1/100 of the orbital period, show, that the distance at all times other than the time of aphelion passage is less.
Own work
AstroOgier