Dwarf planet Fernández and Gonzalo Tancredi: they proposed an intermediate category for objects large enough to be round but which had not cleared their orbits of planetesimals. Dropping Charon from the list, the new proposal also removed Pluto, Ceres, and Eris, because they have not cleared their orbits. The IAU's final Resolution 5A preserved this three-category system for the celestial bodies orbiting the Sun. It reads: Although concerns were raised about the classification of planets orbiting other stars, the issue was not resolved; it was proposed instead to decide this only when such objects start to be observed. The term "dwarf planet"
Atmosphere of Pluto molecules of nitrogen and 5×10 molecules of methane every second. This presumes a loss of several centimeters of nitrogen ice and several dozen meters of methane ice during the lifetime of the Solar System. Molecules with high enough velocity, which escape into outer space, are ionized by solar ultraviolet radiation. As the solar wind encounters the obstacle formed by the ions, it is slowed and diverted, possibly forming a shock wave upstream of Pluto. The ions are "picked up" by the solar wind and carried in its flow past the dwarf planet to form an ion or plasma tail. The