PARIS (AFP) - Once the proud outermost planet of the Solar System, Pluto has been consigned to the status of a small-town telephone number after the world's paramount astronomical body tore up its membership of the cosmic A-list.
The enigmatic, icy world spotted in 1930 has been given the official monicker of 134340 Pluto and lumped among 136,562 asteroids and other small bodies by the Minor Planet Center (MPC), part of the Paris-headquartered International Astronomical Union (IAU).
Pluto's satellites, Charon, Nix and Hydra, have been numbered 134340 I, 134340 II and 134340 III respectively under the latest minor planet list, compiled on September 7.
The IAU last month declared Pluto to be a "dwarf planet" that should not belong among the hallowed ranks of Mercury, Earth, Venus, Mars, Jupiter, Saturn, Uranus and Neptune.
The organisation is now drawing up a "dwarf planet" catalogue whose initial members will include Pluto, the large asteroid Ceres and a distant object, 2003 UB313, unofficially named Xena.
Until the IAU meeting, 2003 UB313 had laid claim to being the Solar System's 10th planet.
Rebel astronomers are circulating a petition, contesting the "dwarf planet" definition as unscientific and the decision on Pluto as undemocratic. They intend to hold a conference next year that, in their view, will overhaul the definition of a planet.
Pluto's status had long been contested by astronomers who said its tiny size, odd orbit and orbital plane precluded it from joining the other acknowledged planets.
By the new IAU yardstick, a planet has "cleared the neighbourhood around its orbit" -- in other words, it is massive enough to wield a gravity that clears rocks and other debris on its orbital path.