Hi there. The recently discovered (year 2002) object actually lies outside of Pluto and is not actually a planet. It belongs to a group of objects that make up the Kuiper Belt. The Kuiper Belt is a grouping of icy planetissimals that orbit outside of Neptune. Many of the comets that visit us in the inner solar system originate in the Kuiper Belt. There is currently an international commission setup to name the object.