The only difference between a planet and a dwarf planet is the area surrounding each celestial body. A dwarf planet has not cleared the area around its orbit, while a planet has. Since the new definition, three objects in our solar system have been classified as dwarf planets: Pluto, Ceres and Eris.UMMARY: Major discoveries in the past decade have forced astronomers to review the definition of a planet. Our solar system now has three classified dwarf planets: our beloved Pluto, Eris, and Ceres.