The figure shows the elliptical orbit of a celestial object around the Sun (yellow circle). At the point which is marked with a green dot, the distance to the Sun is least, it is designated as the perihelion of the orbit. The perihelion distance is marked with a fat red line. The other thin red 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 perihelion passage is larger.
Own work
AstroOgier