List of dwarf-planet candidates

It is estimated that there may be 200 dwarf planets in the Kuiper belt of the outer Solar System and possibly more than 10,000 in the region beyond. The International Astronomical Union (IAU) has accepted four: Pluto, Eris, Haumea, and Makemake, as well as Ceres in the inner Solar System.

In 2008, the IAU modified its naming procedures such that objects considered most likely to be dwarf planets receive differing treatment than others. Objects that have an absolute magnitude (H) less than +1 (and hence a minimum diameter of 838 kilometres (521 mi) if the albedo is below 100%) are overseen by two naming committees, one for minor planets and one for planets. Once named, the objects are declared to be dwarf planets. Makemake and Haumea are the only objects to have proceeded through the naming process as presumed dwarf planets; currently there are no other bodies that meet this criterion. All other bodies are named by the minor-planet naming committee alone, and the IAU has not stated how or if they will be accepted as dwarf planets.

The qualifying feature of a dwarf planet is that it "has sufficient mass for its self-gravity to overcome rigid-body forces so that it assumes a hydrostatic equilibrium (nearly round) shape". Current observations are generally insufficient for a direct determination as to whether a body meets this definition. Also, a dwarf planet may not be the satellite of another body, even though several moons (such as Titan) are larger than the recognized dwarf planets.

Based on a comparison with the icy moons that have been visited by spacecraft, such as Mimas (round at 400 km in diameter) and Proteus (irregular at 410–440 km in diameter), Michael Brown estimated that an icy body relaxes into hydrostatic equilibrium at a diameter somewhere between 200 and 400 km.

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