Why do they call them dwarf planets?
Because more Pluto-sized objects were being located in its area of the solar system (the Kuiper Belt), the IAU decided to limit “planet” status only to the eight large bodies that dominate their respective orbital areas, as far out as Neptune. So the potential for a constantly-changing and contentious count of ‘planets’ would be avoided (reminiscent of the “moons of Jupiter”, which were classically 12 but now number 63).
