This paper describes the discovery of the dwarf planet Ixion in 2001. Ixion is a trans-Neptunian object located in the Kuiper belt beyond the orbit of Neptune. It was discovered by astronomers at the Cerro Tololo Inter-American Observatory in Chile.
28978 Ixion (; provisional designation 2001 KX76) is a large trans-Neptunian object. It is located in the Kuiper belt, a region of icy objects orbiting beyond Neptune in the outer Solar System. Ixion is classified as a plutino, a dynamical class of objects in a 2:3 orbital resonance with Neptune. It was discovered in May 2001 by astronomers of the Deep Ecliptic Survey at the Cerro Tololo Inter-American Observatory, and was announced in July 2001. The object is named after the Greek mythological figure Ixion, who was a king of the Lapiths.