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Dwarf Planet

A body in our solar system that is larger than a comet or asteroid but not large enough to qualify as a major planet. This category was created by the International Astronomical Union in 2006. A dwarf planet is large enough that its gravity can pull it into a roughly spherical shape, but not large enough to clear its orbit around the Sun of other objects. As of 2011, there are five dwarf planets in the solar system: Pluto, Ceres, Eris, Makemake, and Haumea (which is not spherical, but is shaped more like an egg or a potato). Ceres is in the asteroid belt, while the others are beyond the orbit of Neptune, the eighth planet from the Sun.

Featured Images

True-color view of Ceres

Ceres at Opposition February 1, 2018

Rings encircle the dwarf planet Haumea

Ringed Dwarf Planet December 22, 2017

Dawn images of north pole of Ceres

Over the Top April 17, 2015

Dawn image of Ceres, January 25, 2015

Getting Closer January 28, 2015

Three dwarf planets shown to scale with Earth and Moon

Dwarf Planets January 5, 2015

Radio Programs

Water Worlds II Tracing a vanished ocean January 16, 2018

Ringed Dwarf Rings around a distant iceball December 22, 2017

Cold Discoveries Cold discoveries beyond the planets December 28, 2016

Stolen Sedna A case of interstellar theft May 16, 2016

More Dawn at Ceres Looking for water on an asteroid March 4, 2015

Icy Time Capsules Refugees from the realm of the giants January 7, 2015

Moon and Jupiter Closing in on two dwarf planets January 6, 2015

Eris Reflections on a bright dwarf planet January 5, 2015

Dwarf Planets A new name for leftover building blocks January 4, 2015