Dwarf planets

A selection of sites and links about dwarf planets in general and about some of the largest dwarf planets recently discovered in our survey at Palomar Observatory.

• How many dwarf planets are there? (And what are they?)

  This continuously updating list records the likely and possible dwarf planets discovered in our solar system so far.

• The dwarf planet page

  What is a dwarf planet? Explanations of this new class written at the time of the new definition along with a complete list of the likely candidates that met the criteria for dwarf planethood at that time.

• The eight planets

  An explanation of why astronomers decided that Pluto should no longer be considered a planet and why eight is a good number of planets.

• Eris

  The largest dwarf planet, and the object whose discovery prompted the decision to reclassify all of these objects, including Pluto, as dwarf planets.

• A Requiem for Xena

  A farewell to the former planet formerly known as Xena, now officially known as the dwarf planet named Eris.

• 2003 EL61 = Haumea

  Information about Haumea, a rapidly spinning Pluto-sized football-shaped ice-coated deformed rock in the outer solar system with a family of icy debris around it.

• Sedna

  the first of a new class of objects beyond the Kuiper belt and a fossilized record from the birth of the solar system.

• Orcus

  Pluto's slightly smaller twin.

• Quaoar

  The first to be discovered (in 2002) of the truly gigantic Kuiper belt objects. Named for the creation deity of the Tongva tribe.



• Thoughts on the planet debate

  Commentary written while astronomers were debating the new definition of the word "planet."