Definition of planet In the original draft proposal, an exception was made for Pluto and its largest satellite, Charon, which possess a barycenter outside the volume of either body. The initial proposal classified Pluto–Charon as a double planet, with the two objects orbiting the Sun in tandem. However, the final draft made clear that, even though they are similar in relative size, only Pluto would currently be classified as a dwarf planet. However, some have suggested that the Moon nonetheless deserves to be called a planet. In 1975, Isaac Asimov noted that the timing of the Moon's orbit is in tandem with the
Dwarf planet recognized five bodies as dwarf planets since 2008: Ceres, Pluto, Eris, Haumea, and Makemake. Ceres and Pluto are known to be dwarf planets through direct observation. Eris is recognized as a dwarf planet because it is more massive than Pluto (measurements by "New Horizons" indicate that Pluto's diameter is larger than that of Eris), whereas Haumea and Makemake qualify based on their absolute magnitudes. In relative distance from the Sun, the five are: Mike Brown considers an additional six trans-Neptunian objects to be "nearly certainly" dwarf planets with diameters at or above 900 kilometers. These objects are: Tancredi et al.