WASHINGTON: Pluto, demoted from planet status in 2006, got a consolation prize — it and other dwarf planets like it will be called plutoids.

The International Astronomical Union said in a statement on Wednesday that its executive committee meeting in Oslo, Norway, decided on the term.

Plutoids will be defined as celestial bodies in orbit around the Sun farther away than Neptune. They must have near-spherical shape, and must not have swept up other, smaller objects in their orbits, said the organization, which names newly discovered planets and other celestial bodies. The two known and named plutoids are Pluto and Eris, but astronomers expect to find more.

Another dwarf planet, Ceres, does not merit the plutoid designation because it is in the asteroid belt between Mars and Jupiter.

When Pluto was demoted, the astronomical union always planned on naming the new category of objects after the former planet, but had to find the right name, said IAU president Catherine Cesarsky, a French astrophysicist. Their first choice, pluton, was already used by geologists.

The astronomers' action makes Pluto more important, Cesarsky said. Instead of being a “puny” outer planet, Pluto is now a “prototype of a new type of fascinating objects”, she said. “It doesn't really roll off the tongue very well,” said Mike Brown, the California Institute of Technology astronomer who discovered Eris. “Maybe it'll make it.”

Source: The Times of India
Date: 13 June 2008