Plutoid

trans-Neptunian dwarf planet

A plutoid or ice dwarf is a dwarf planet that orbits the sun farther than Neptune. This concept was defined by the International Astronomical Union General Assembly on Prague under votes, but without choosing the terminology according to resolution 6A of this general assembly entitled Definition of Pluto-class objects. Its definition is:

Celestial bodies orbiting the Sun at a distance greater than that of Neptune, with sufficient mass for their own gravity to overcome rigid body forces such that they assume an almost spherical shape of hydrostatic equilibrium and that have not emptied their orbit of neighboring bodies.

Therefore, any object that meets the definition of dwarf planet and also belongs to the Trans-Neptunian objects will be considered a plutoid. Eight objects are now classified as plutoids: Pluto, Orcus, Haumea, Makemake, Quaoar, Sedna, Gonggong, and Eris.

The satellites of the plutoids are not plutoids, even though they are massive enough to be gravitationally rounded.

Ceres is not a plutoid hence it's in the asteroid belt between Mars and Jupiter and is the only dwarf planet that is not a plutoid.

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