There were totally 9 planets in our Solar system orbiting a star called The Sun. But in August 2006, the International Astronomical Union (IAU) officially declared that Pluto belongs with another category called dwarf planet.
A planet should have the following three criteria
1. It orbits around the sun, but it should not be a state
2. It should have sufficient mass, so that it remains spherical in shape
3. It should have cleared its neighborhood around its orbit.
What is the difference between a planet and a dwarf planet? By the above mentioned criteria, dwarf planets satisfy the two criteria’s and fails to satisfy the third criteria. In case of a dwarf planet, the area around its orbit will not be clear enough. The orbit of Pluto crosses with the orbit of Neptune (neighboring planet).
The list of dwarf planets in our Solar system are Ceres, Pluto, Eris, Makemake, Haumea. Ceres is present in the region of Asteroid belt. Pluto, Eris, Makemake and Haumea originate from the Kuiper belt region.
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