What is the dwarf planet?

Dwarf is a new category of heavenly body created by the International Astronome Union in 2006. It includes heavenly bodies massive enough to be spherical, in orbit around the Sun, which is not satellites. The key factor in the dwarf planet from the dwarf planet is that the planet had to succeed in cleaning the area of ​​its orbit from the debris and other objects, while the dwarf planet was not.

When the category of dwarf planets was created, the three bodies were immediately classified as such: Ceres, the largest asteroid, now the dwarf planet; Pluto, in the Kuiper belt, degraded from the state of the planet; And Eris, a dispersed disc object located far beyond Pluto orbit. It was the discovery of Eris, which partly caused the international astronomers to define more precisely what the word "planet" meant.

Despite the name "dwarf planet", the dwarf planets are not considered to be a subgroup of the planets, but rather in another category. Objects ever less than dwarf planets, such as those thatThey do not have sufficient mass to spherical, they are called small bodies of solar system, which include comets and asteroids.

Although only three dwarf planets have recognized, astronomers suspect that many of the far reach of the solar system exist up to 200. There are many potential candidates for dwarf plantations that must be studied closer to confirm their status. To make the celestial body roughly spherical, it requires a diameter of at least 400 km. The smallest known spherical body is today's mimas.

There are many Trans-Neptune objects with averages greater than 400 km: Varuna, Orcus, IXion, Quaoar, 2003el _{61 , 2005FY 9 and several others. Although we can estimate their average, it is more difficult to estimate whether they are roughly spherical or not. This will require more powerful telescopes. There are also several large asteroids that can be dwarf planets: vest, palLas and Hygiea, second, third and fourth largest asteroids after Ceres.}