Pluto is now just a number:

Pluto has been given a new name to reflect its new status as a dwarf planet.

On Sept. 7, the former 9th planet was assigned the asteroid number 134340 by the Minor Planet Center (MPC), the official organization responsible for collecting data about asteroids and comets in our solar system...

Pluto's companion satellites, Charon, Nix and Hydra are considered part of the same system and will not be assigned separate asteroid numbers, said MPC director emeritus Brian Marsden. Instead, they will be called 134340 I, II and III, respectively...

Other notable objects to receive asteroid numbers included 2003 UB313, also known as "Xena," and the recently discovered Kuiper Belt objects 2003 EL61 and 2005 FY9. Their asteroid numbers are 136199, 136108 and 136472, respectively.