Dwarf Planets
Created | Updated Oct 11, 2006
Dwarf planet is a category of planet created on 24th August 2006 in Prague by the International Astronomical Union.
What is a Dwarf Planet?
A dwarf planet is defined as an object that orbits the sun, has sufficient self-gravity to obtain a round shape, has not "cleared the neighbourhood" around its orbit, and is not a satellite of another planet, dwarf planet, or other non-stellar body.
Planets and Dwarf Planets Compared
Most of the requirements for the two are the same. The major difference is that a planet has "cleared the neighbourhood", while a dwarf planet has not. "Cleared the neighborhood" means that nearby asteroids are pulled into orbit around the planet as a moon.
Why do we have Dwarf Planets?
For many years, it was debated whether Pluto was an actual planet or not. People argued that if Pluto was a planet, so was the asteroid, Ceres; Pluto's moon, Charon; and 2003 UB313, an object orbiting the sun beyond Pluto. 2003 UB313 has recently been given the official name "Eris," after the Greek goddess of chaos.
After much debating, scientist decided to create a new category rather then force schoolchildren to learn the name of three extra planets.
A good number of astronomers don't like the new classification, calling it "embarassing" and "inconsistent."1
Which Bodies are Dwarf Planets?
Along with Pluto, both Ceres and Eris are classified as dwarf planets. Charon is now classified as a "small solar system body." There are other bodies that astronomers are thinking of considering as dwarf planets. Some sources claim that there are up to 45 such bodies. The following is a short list of potential dwarf planets.2
- 2005 FY9 ("Easterbunny")
- Orcus
- Sedna
- 2003 EL61("Santa")
- Quaoar
- Charon
- 2002 TC302
- Varuna
- 2002 UX25
- 2002 TX300
- Ixion
- 2002 AW197
- Vesta
- Pallas
- Hygeia
1According to BBC News2This list was compiled from The Encyclopedia of Astrobiology, Astronomy, and Space Flight and Wikipedia.
