Fourth planet in Canopus system in the Dune Universe. Planet radius is 8112 km. Uninhabited. 5 other planets exist in the system, Arrakis, Menaris, Seban, Ven and Revona. Because of similarities of size and orbit, Menaris and Extaris are informally referred to as "the Twins." Their combination is responsible for the highly eccentric orbit of the third planet, Arrakis.