Dwarf planets didn't actually exist until 2006. Then they were separated into a new class of space objects. The purpose of this transformation was to introduce an intermediate link between the major planets and numerous asteroids to prevent confusion in the names and statuses of new bodies found beyond the orbit of Neptune.
Definition
Then, back in 2006, the next meeting of the IAU (International Astronomical Union) was held. On the agenda was the question of specifying the status of Pluto. During the discussions, it was decided to deprive him of the " title" of the ninth planet. The IAU has developed definitions for some space objects:
- A planet is a body orbiting the Sun that is massive enough to maintain hydrostatic balance (i.e., have a rounded shape) and clear its orbit of other objects.
- Asteroid - a body that orbits the Sun, with a small mass that does not allow it to achieve hydrostatic equilibrium.
- Dwarf planet - body,orbiting the Sun, maintaining hydrostatic balance but not massive enough to clear an orbit.
Pluto was included among the latter.
New status
Pluto is also classified as a trans-Neptunian object. Like some other dwarf planets, it belongs to the Kuiper belt bodies. The impetus for the revision of the status of Pluto was the numerous discoveries of objects in this remote part of the solar system. Among them was Eris, which surpasses Pluto in mass by 27%. Logically, all these bodies should have been classified as planets. That is why it was decided to revise and specify the definitions of such space objects. This is how dwarf planets appeared.
Tenth
It wasn't just Pluto who was "downgraded". Eris, prior to the IAU meeting in 2006, claimed the " title" of the tenth planet. It surpasses Pluto in mass, but is inferior to it in size. Eris was discovered in 2005 by a group of American astronomers looking for trans-Neptunian objects. Initially, she was called Xena or Xena, but later the modern name was used.
Eris, like other dwarf planets of the solar system, has hydrostatic balance, but is unable to clear its orbit from other space bodies.
Third on the list
The next largest after Pluto and Eris is Makemake. This is a classic object. Kuiper belts. The name of this body has an interesting history. As always, after opening it was given the number 2005 FY9. For a long time, the team of American astronomers who discovered Makemake called it the "Easter Bunny" among themselves (the discovery was made a few days after the holiday).
In 2006, when a new column “Dwarf Planets of the Solar System” appeared in the classification, it was decided to name 2005 FY9 differently. Traditionally, classical Kuiper belt objects are named after creation deities. Make-make is the creator of mankind in the mythology of the Rapanui, the original inhabitants of Easter Island.
Haumea
Dwarf planets of the solar system include another trans-Neptunian object. This is Haumea. Its main feature is very fast rotation. Haumea in this parameter is ahead of all known objects with a diameter of more than a hundred meters in our system. Among the dwarf planets, the object ranks fourth in size.
Ceres
Another cosmic body belonging to this class is located in the main asteroid belt, lying between the orbits of Jupiter and Mars. This is Ceres. It was opened at the beginning of 1801. For some time it was considered a full-fledged planet. In 1802, Ceres was classified as an asteroid. The status of the cosmic body was revised in 2006.
Dwarf planets differ from their large neighbors mainly in the inability to clear their own orbit fromother bodies and space debris. It is difficult to say now how convenient such an innovation is to use - time will tell. So far, the controversy over the downgrading of Pluto has only subsided a little. However, the value of the former ninth planet and similar bodies for science remains high regardless of how they are called.
