Pluto in approximate true colour based on Hubble Space Telescope albedo data Haumea with its moons, Hiʻiaka and Namaka (artist's conception) Eris and its moon Dysnomia as seen with the Hubble Space Telescope
Makemake , minor-planet designation 136472 Makemake , is a dwarf planet and perhaps the largest Kuiper belt object (KBO) in the classical population , [ nb 5 ] with a diameter that is about 2/3 the size of Pluto . [ 9 ] [ 17 ] Makemake has no known satellites, which makes it unique among the largest KBOs and means that its mass can only be estimated. Its extremely low average temperature, about 30 K (−243.2 °C), means its surface is covered with methane , ethane , and possibly nitrogen ices. [ 14 ] Initially known as 2005 FY 9 and later given the minor-planet number 136472, it was discovered on March 31, 2005, by a team led by Michael Brown , and announced on July 29, 2005. Makemake was recognized as a dwarf planet by the International Astronomical Union (IAU) in July 2008. [ 18 ] [ 17 ] [ 19 ] [ 20 ] Its name derives from Makemake in the mythology of the Rapanui people of Easter Island . [ 17 ]
Haumea , minor-planet designation 136108 Haumea , is a dwarf planet [ 19 ] located beyond Neptune's orbit. Just one-third the mass of Pluto , [ 20 ] it was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory in the United States and, in 2005, by a team headed by J. L.
Ceres , minor-planet designation 1 Ceres , is the only dwarf planet in the inner Solar System , and the largest asteroid . [ 19 ] [ 20 ] [ 21 ] It is a rock–ice body 950 km (590 mi) in diameter, and though the smallest identified dwarf planet, it constitutes a third of the mass of the asteroid belt . [ 22 ] [ 23 ] Discovered on 1 January 1801 by Giuseppe Piazzi , [ 24 ] it was the first asteroid to be identified, though it was classified as a planet at the time. [ 25 ] It is named after Ceres , the Roman goddess of growing plants, the harvest, and motherly love.
Eris , minor-planet designation 136199 Eris , is the most massive known dwarf planet in the Solar System and the ninth most massive body known to orbit the Sun directly. [ d ] It is estimated to be 2326 (±12) km in diameter, [ 9 ] and 27% more massive than Pluto , or about 0.27% of the Earth 's mass. [ 10 ] [ 16 ] Eris was discovered in January 2005 by a Palomar Observatory -based team led by Mike Brown , and its identity was verified later that year. It is a trans-Neptunian object (TNO) and a member of a high-eccentricity population known as the scattered disc .
Pluto , formal designation 134340 Pluto , is the second-most-massive known dwarf planet in the Solar System (after Eris ) and the tenth-most-massive body observed directly orbiting the Sun . [ h ] Originally classified as the ninth planet from the Sun, Pluto was recategorized as a dwarf planet and plutoid owing to the discovery that it is only one of several large bodies within the Kuiper belt . [ i ] Like other members of the Kuiper belt, Pluto is composed primarily of rock and ice and is relatively small, approximately one-sixth the mass of the Earth 's Moon and one-third its volume. It has an eccentric and highly inclined orbit that takes it from 30 to 49 AU (4.4–7.4 billion km) from the Sun. This causes Pluto to periodically come closer to the Sun than Neptune . As of 2011, it is 32.1 AU from the Sun. [ 15 ] From its discovery in 1930 until 2006, Pluto was classified as a planet .