Dwarf planets

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Term: Dwarf planets

A new category of astronomical objects in the solar system introduced in a resolution by the 26th General Assembly of the International Astronomical Union (IAU) on August 24, 2006. The characterizing properties are as follows: 1) It is in orbit around the Sun; 2) It has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape; 3) It has not 'cleared the neighbourhood' around its orbit; and 4) It is not a satellite of a planet, or other non-stellar body. The property 3 reclassified Pluto from a planet to a dwarf planet because it has not cleared the neighborhood of its orbit (the Kuiper Belt). The largest known dwarf planets are: Eris, Pluto, Ceres, Makemake, and 2015 RR245.

Created 2023.04.16
Last Modified 2023.04.16
Contributed by Ryan McGranaghan