Dwarf Planets in the Solar System

Dwarf Planets

Listed here are the five (as of 2012) dwarf planets in decreasing order of mass.

Eris

Eris is the most massive of the dwarf planets and is the ninth most massive body to orbit the sun. It is a TNO or trans-Neptunian object, which are a collection of objects orbiting the sun at a greater distance than Neptune. Discovered in January 2005 it is also known to have one moon, Dysnomia and it is currently (barring comets) the furthest natural object in the solar system.

Pluto

Pluto was discovered in 1930 and for 76 years was classified as a ninth planet in the solar system. On August 24 2006 is was newly classified as a dwarf planet. Pluto has four known moons and is is part of the Kuiper belt

Ceres

Ceres was discovered in 1801 (before Neptune) and was first though to be a planet but classified as an asteroid about a half century later. Ceres is the largest object in the asteroid belt between Jupiter and Mars and is the only dwarf planet in the inner solar system. 

Makemake

Makemake is thought to be the largest Kuiper Belt object and is unique among the outer dwarf planets because it is thought to have no satellite. It was discovered in 2005 and was officially designated a dwarf planet in 2008. It is named after the creator of humanity in the mythology of Easter Island.

Haumea

Haumea was discovered in 2004 and was officially designated a dwarf planet in 2008. It has an extremely elongated orbit which make it unique among the dwarf planets and has an orbital period of 283 earth years. It has two known moons which along with the dwarf planet itself are members of the collisional family which are a group of objects thought to be remnant debris from a large shattered object.