Additional Possibilities
After Ceres, the next-most-massive body in the asteroid belt, Vesta, might also be classified as a dwarf planet, as its shape appears to deviate from hydrostatic equilibrium mainly because of massive impacts that occurred after it solidified. The definition of dwarf planet does not address this issue. Data from the Dawn probe, which orbited Vesta in 2011–2012, may help clarify matters.
Many trans-Neptunian objects (TNOs) are thought to have icy cores and therefore would require a diameter of perhaps 400 km (250 mi)—only about 3% of that of Earth—to relax into gravitational equilibrium, making them dwarf planets of the plutoid class. Although only rough estimates of the diameters of these objects are available, as of 2011 it was believed that a hundred of the known bodies beyond Neptune were probable dwarf planets. A team is investigating thirty of these, and believe that the number will eventually prove to be about 200 in the Kuiper belt and many more beyond.
Read more about this topic: Dwarf Planets
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