TNO Colors

Explanation: An illustration of the color distribution of trans-Neptunian objects (TNOs). The position of an object represents the two color indices, V-B (blue color index, i.e. the difference in the magnitude of the object observed through a visual (green-yellow) and a blue filter) and V-R (red color index, the difference in the magnitude between red and visual filters). The size of a sphere illustrates the object's size relative to others.

Pluto

Image credit: Wikipedia.