Pluto has at least two recently discovered additional satellites that are smaller than Charon. If these smaller satellites also orbit the “barycentre”, does this make Pluto a “quadruple planet”?
No. The two newly discovered smaller bodies in orbit around Pluto are too small and not massive enough for their self-gravity to force them in to a spherical shape. Therefore neither of these bodies independently satisfies the definition of “planet.” The fact that their size (mass) and shapes does not qualify them as planets implies that they must be called satellites, even though the center of gravity (called the “barycentre”) about which they orbit is located outside the surface of Pluto.
