The celestial body classified as a dwarf planet is Pluto. Once considered the ninth planet in our solar system, Pluto was reclassified as a dwarf planet by the International Astronomical Union in 2006 due to its size and the criteria it did not meet for full planetary status. Pluto has a highly elliptical orbit and is primarily composed of ice and rock. It is located in the Kuiper Belt and has five known moons, with Charon being the largest. The reclassification of Pluto sparked discussions about planetary definitions and our understanding of the solar system.