Ixion is a plutino -LRB- an object that has a NUMBER@1 orbital resonance with LOCATION@1 -RRB- and a potential dwarf planet ; its estimated diameter of NUMBER@2 km makes it the third largest plutino .

Ixion is a plutino -LRB- an object that has a NUMBER@1 orbital resonance with LOCATION@1 -RRB- and could be a dwarf planet . Astronomers think that it has a diameter of about NUMBER@2 km , which makes it the third biggest plutino .
