Dwarf planet

Rare card · No. 21495

A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be gravitationally rounded, but insufficient to achieve orbital dominance like the eight classical planets of the Solar System. The prototypical dwarf planet is Pluto, which for decades was regarded as a planet before the "dwarf" concept was adopted in 2006. Many planetary geologists consider dwarf planets and planetary-mass moons to be planets, but since 2006 the IAU and many astronomers have excluded them from the roster of planets. Dwarf planets are capable of being geologically active, an expectation that was borne out in 2015 by the Dawn mission to Ceres and the New Horizons mission to Pluto. Planetary geologists are therefore particularly interested in them. Astronomers are in general agreement that at least the nine largest candidates are dwarf planets – in rough order of decreasing diameter, Pluto, Eris, Haumea, Makemake, Gonggong, Quaoar, Sedna, Ceres, and Orcus. A considerable...

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