Quick Navigation

Dwarf Planets

The International Astronomical Union (IAU) decided in 2006 to create a new classification of celestial bodies: Dwarf Planets. Here are the criteria the IAU has set forth to define a planet:

  • Heliocentric Orbit - A planet orbits the sun.
  • Hydrostatic Equilibrium - A planet needs to be large enough for it's gravity to make it spherical.
  • Dominant Orbital Body - A planet does not share it's orbit.

This new term defines all bodies that look like a planet, but fall short of the planetary definition in some way. For example, Ceres shares it's orbit with the asteroid belt (Planets do not share orbits). Pluto shares it's orbit with Charon and the Kuiper belt. Here is a list of the Dwarf Planets we have so far:

Name Distance (AU) Diameter (km) Year
Ceres 2.77 974.6 1801
Pluto 39.48 2,306 1930
Haumea 43.34 1150 2005
Makemake 45.79 1500 2005
Eris 67.67 2400 2005

New Candidates

The Dwarf Planets above were only an Initial Offering from the IAU to help define the term. There are many other bodies that fit the criteria of Dwarf Planet and will be considered:

Name Distance (AU) Diameter (km) Year
Orcus 39.12 1,200 2004
Ixion 39.65 900 2001
Huya 39.76 480 2000
Varuna 42.90 850 2000
2002 TX300 43.11 800 2002
Quaoar 43.58 1,200 2002
2002 AW197 47.30 900 2002
2002 TC302 55.02 1,100 2002
1996 TL66 82.90 600 1996
Sedna 88 1500 2003
Charon 39.48 603.5 1978

 

Back to Main

Advertisement: