Unless you are excluding Pluto deliberately for not being "a planet", its moon Charon has half the diameter of Pluto. They are even both orbiting a common cente

Unless you are excluding Pluto deliberately for not being "a planet", its moon Charon has half the diameter of Pluto. They are even both orbiting a common center of gravity outside Pluto. https://en.wikipedia.org/wiki/Charon_(moon) https://en.wikipedia.org/wiki/Charon_(moon)