Pluto may yet lose planet status

We were about to gain a horde of new planets; now we might lose one instead.

In Prague, astronomers are trying to define what it means to be a planet. A draft definition released on Wednesday would have extended the club from the conventional nine to twelve, and soon to many more (see Three new planets may join solar system).

But on Friday, astronomers at the meeting suggested a different scheme – one that would instead relegate Pluto to the status of "dwarf planet".

Wednesday's original proposal was made by the International Astronomical Union's official planet definition committee (read the IAU's proposed definitions of a planet, a pluton and other objects). Their suggestion was to include any round object that independently orbits the Sun – including Ceres (formerly considered an asteroid), Pluto's companion Charon, and the distant body currently known as Xena.