Charon, is the first discovered Pluto satellite. It has 1,192 kilometers of diameter 1/3 of Pluto and is to 19,640 kilometers of the planet forming with him a binary dwarf planet system. But in the meeting of the IAU celebrated in the Prague in August of 2006 dwarf planet of our Solar System was adopted to Coronte like third comprising of dwarf planet system a binary with Pluto.

                With time, the gravity has restrained the rotations of Charon and Pluto, reason why now they present/display always the same face the one to the other. The rotation of this pair is unique in the Solar System. It seems as if they were united by an invisible bar and they turned around a center located in the bar, closest to Pluto, than Charon has 7 times more mass than. Usually one says that they constitute a double planet.

                By its density, Pluto seems fact of rocks and ice. However, its satellite is very light. This difference makes think that they formed separately, and later they were united, hypothesis that not yet is defined.


Pluto and Charon

3º and 4º dwarf planet of the Solar System


        Pluto has an extremely tenuous atmosphere, formed by nitrogen, methane and monoxide of carbon, that is congealed and colapsa on its surface as the dwarf planet moves away of the Sun; it is this evaporation and later freezing the one that caused the variations in the Albedo of the dwarf planet, detected by means of photoelectric photometers in years 50 (Kuiper and others). As the dwarf planet came near the changes went away making smaller, diminishing when it was in the orbital perihelion (1989); one hopes that these changes of Albedo return to repeat themselves, but to the inverse one, as the planet moves away of the sun course to its aphelion.


Outer satellites: Hydra and Nix

            The 31 of October of 2005 the Space Telescope Hubble announced the possible discovery of two additional satellites of so large minor. These moons were observed in May of 2005 and confirmed its existence in June of 2006 they have received the names of Nix (provisional name S/2005 P 1)) and Hidra (provisional name S/2005 P 2). The name of both volume having them in account to two, since their initials NH render New tribute to the space probe Horizontes(NH), that took off in 2006 to Pluto. The preliminary observations are consistent with both bodies orbiting in the same plane that Charon and to distances two and three superior times. Both pretend to have between 100 and 150 km of diameter.



                    In the page Web you can obtain more data of each one of our planets and the dwarf planets defined by the IAU of our Solar System.


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