Dwarf Planets

Dwarf Planets

About Dwarf Planets

A dwarf planet, as defined by the International Astronomical Union (IAU), is a celestial body in direct orbit of the Sun that is massive enough that its shape is controlled by gravitational forces rather than mechanical forces (and thus an ellipsoid in shape), but has not cleared its neighboring region of other objects. More explicitly, it is a planetary-mass object_having sufficient mass to overcome its compressive strength and achieve hydrostatic equilibrium_but not a satellite. The term dwarf planet was adopted in 2006 as part of a three-way categorization of bodies orbiting the Sun, brought about by an increase in discoveries of trans-Neptunian objects that rivaled Pluto in size, and finally precipitated by the discovery of an even more massive object, Eris.

Contributions by RandomCritic, Derek Balsam, and Nbound.