Facts about Dwarf Planets for Kids

The “dwarf planet” is a term coined by IAU (International Astronomical Union) in 2006 to explain the celestial objects that resemble planets that are generally smaller that the planets. After Eris was discovered in 2005, which has the same size as Pluto, the Pluto which was given the status as the 9th planet of our solar system in 1930 was demoted to the status of dwarf planet in 2006 by IAU.


What is a dwarf planet?

According to the IAU (International Astronomical Union), which sets definitions for planetary science, a dwarf planet is a celestial body that:
~ Orbits the Sun.
~ Has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape.
~ Has not cleared the neighborhood around its orbit. It means that their route crosses over another object orbiting the Sun.
~ Is should be not a satellite. 

Facts about dwarf planets:

~ As of 2011, the IAU (International Astronomical Union) has officially recognized 5 dwarf planets. They are Pluto, Ceres, Eris, Makemake & Haumea.

~ It is estimated that there are more than 100 dwarf planets yet to be discovered.

~ The dwarf planets that orbit beyond Neptune are called Plutoids. As of now there are 4 plutoids they are Pluto, Eris, Makemake & Haumea.

~ Ceres is the only dwarf planet to revolve in the asteroid belt of Mars and Jupiter.

More about the five dwarf planets:

Pluto:

Pluto was discovered on February 18, 1930, by Clyde Tombaugh. Pluto is named after Roman god. It orbits in the Kuiper Belt. It is the second largest dwarf planet. It was considered as the 9th planet of our solar system 1930 until 2006 but the planet Pluto was reclassified as a dwarf planet on August 24, 2006.

Ceres:

Ceres was discovered on January 1, 1801 by Giuseppe Piazzi. Pluto is named after Roman god. It orbits in the asteroid belt in between Mars and Jupiter. Ceres is the largest object in the asteroid belt. It was classified as an asteroid but was reclassified as a dwarf planet on September 13, 2006.

Eris:

Eris was discovered on January 5, 2005 by Mount Palomar Observatory, California based team of Mike Brown, Chad Trujillo, and David Rabinowitz. Eris is named after the Greek god. It is the largest dwarf planet. It was initially classified as the 10th planet but was reclassified as dwarf planet on September 13, 2006.

Makemake:

Makemake was discovered on March 31, 2005 by Mount Palomar Observatory, California based team led by Michael Brown. Makemake is named after Easter Island god. It is the third largest dwarf planet. It was classified as dwarf planet on July 11, 2008.

Haumea:

Haumea was discovered on December 28, 2004. Haumea is named after the Hawaiian goddess. It was classified as a dwarf planet on September 17, 2008.