Why is Pluto now called a dwarf planet?
Pluto now falls into the dwarf planet category on account of its size and the fact that it resides within a zone of other similarly-sized objects known as the transneptunian region. Q: Is Pluto’s satellite Charon a dwarf planet? A: For now, Charon is considered just to be Pluto’s satellite. The idea that Charon might qualify to be called a dwarf planet in its own right may be considered later. Charon may receive consideration because Pluto and Charon are comparable in size and orbit each other, rather than just being a satellite orbiting a planet. Most important for Charon’s case as a dwarf planet is that the centre of gravity about which Charon orbits is not inside of the system primary, Pluto. Instead this centre of gravity, called the barycentre, resides in free space between Pluto and Charon. Q: Jupiter and Saturn, for example, have large spherical satellites in orbit around them. Are these large spherical satellites now to be called dwarf planets? A: No. All of the large satellite
