The spacecraft is now heading to the dwarf planet Ceres.

CNN: While you were working: An asteroid just flew by

The probe, which launched in 2007, reached Vesta a few weeks ago, and will be spending about a year there before it departs on its three year journey to the dwarf planet Ceres, also located in the asteroid belt.

FORBES: Stunning Photos of Vesta from Dawn

Choice of a suitably fiddled threshold (say, 1, 000km) would then make Pluto, but not Ceres, a major planet.

ECONOMIST: Pluto out in the cold