I don't know, but a little girl came up with the name for it.
Who Is The First Person Who Discover The 9 Planet?
Although Pluto was reclassified as a 'dwarf planet' in 2006, prior to that it was regarded as the 9th major planet in our solar system. It was identified as such in early 1930, by an astronomer called CLYDE TOMBAUGH working at the Lowell Observatory in Flagstaff, Arizona.