Dwarf planets: Pluto, Eris, Makemake, Haumea

Dwarf planets did not actually exist until 2006. Then they were allocated to a new class of space objects. The goal of this transformation was the introduction of an intermediate link between the large planets and numerous asteroids to prevent confusion in the names and statuses of new bodies detected beyond the orbit of Neptune.

Definition

Then, in the far distant 2006, the next meeting of the 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 of some space objects:

• The planet is a body circling around the Sun, massive enough to maintain hydrostatic equilibrium (that is, to have a rounded shape) and to clear its orbit from other objects.
• The asteroid is a body circling the Sun, possessing a small mass, which does not allow it to achieve hydrostatic equilibrium.
• A dwarf planet is a body circling the Sun, supporting hydrostatic equilibrium, but not massive enough to clear the orbit.

Pluto was among the last.

New status

Pluto is also classified as a trans-Neptunian object. Like some other dwarf planets, it refers to the bodies of the Kuiper belt. The push to revise the status of Pluto was the numerous discoveries of objects in this remote part of the solar system. Among them was Eris, which outnumbered Pluto by 27%. Logically, all these bodies had to be classified as planets. That is why it was decided to revise and concretize the definitions of such space objects. So there were dwarf planets.

Tenth

Not only was Pluto "reduced in rank". Eris before the meeting of the IAU in 2006 claimed to be the "title" of the tenth planet. It surpasses Pluto by mass, but is inferior in size. Eris was discovered in 2005 by a group of American astronomers who were searching for trans-Neptunian objects. Originally it was called Xeno or Xena, but later the modern name was used.

Eris, like other dwarf planets of the solar system, has hydrostatic equilibrium, but is unable to clear its orbit from other cosmic bodies.

Third on the list

The next largest after Pluto and Eris is Makemake. This is a classic Kuiper belt object. An interesting story has the name of this body. As always, after the discovery, he was assigned the number 2005 FY ₉ . For a long time, a team of American astronomers, who discovered Makemake, called it the "Easter rabbit" (the discovery was made a few days after the holiday).

In 2006, when a new graph "Dwarf Planets of the Solar System" appeared in the classification, it was decided to refer to 2005 FY ₉ differently. By tradition, the classical objects of the Kuiper belt are named after the deities associated with the creation. Make-make is the creator of humanity in the mythology of the Rapanui, the ancestral inhabitants of Easter Island.

Haumea

Dwarf planets of the solar system include another trans-neptun 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 one hundred meters in our system. Among the dwarf planets, the object is the fourth largest.

Ceres

Another space body belonging to this class is located in the Main Asteroid Belt, which lies between the orbits of Jupiter and Mars. This is Ceres. It was opened in the beginning of 1801. For some time it was considered a full-fledged planet. And in 1802 Ceres was taken to the asteroids. The status of the cosmic body was revised in 2006.

Dwarf planets from their large neighbors are mainly characterized by their inability to clear their own orbit from other bodies and space debris. How easy it is to use such an innovation, now it is difficult to say - time will tell. For the time being, however, the disputes over the lowering of Pluto's status have only calmed down a bit. However, the value of the former ninth planet and similar bodies for science remains high no matter how they are called.