Britannica
Sources used in this answer
Why are Pluto and Eris also called plutoids?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Kuiper belt
An artist's rendition of a binary object in the Kuiper belt. The two objects depicted orbit each other at the edge of the solar system.
Pluto and Eris are classified as plutoids because they meet the specific criteria established by the International Astronomical Union (IAU) in June 2008.
To be designated as a plutoid, a celestial body must satisfy two primary conditions:
* It must be classified as a dwarf planet.
* It must have an orbit that is farther from the Sun than the planet Neptune.21
While Ceres is also a dwarf planet, it is not considered a plutoid because it is located within the asteroid belt rather than in the outer reaches of the solar system. Essentially, plutoids are large objects found in the Kuiper belt or beyond that are massive enough for their own gravity to have rounded their shape but have not cleared their orbital neighborhoods of other debris.21