Xena an unlikely name for the latest heavenly body

The chance of a new planet being named after New Zealand's television warrior princess, Xena, are probably not high.

The name of a new object in the solar system has to pass muster with the Paris-based International Astronomical Union (IAU), which is made up of 9000 astronomers from throughout the world.

Dr Michael Brown, of the California Institute of Technology, and the team who discovered the planet have christened it Xena, after the warrior played by New Zealand actor Lucy Lawless in the television series, "because we always wanted to name something Xena".

But IAU member and astronomer Pam Kilmartin, of Canterbury University's Mt St John Observatory, said any name would have to be approved by the IAU and naming guidelines were "quite stringent".

A new planet could not be named after a military or political figure, and obviously anything in "bad taste" was out.

She did not know anything about the name Xena but said there was already a minor planet called Xenia, which might spoil Xena's chances.

The new planet was "transneptunian" - beyond Neptune - in the so-called Kuiper Belt, which meant any planet discovered there had to be named after the Greek gods of creation or gods of the underworld, Pam Kilmartin said.

An Auckland University astronomer, Associate Professor Phil Yock, said he was not sure how interested in astronomy Lawless was, "but I'm sure she'd love to have a planet named after her".

The new planet is cold: on a good day, it might touch minus 240C.

Its year is wearyingly long - an orbit of the sun takes about 560 Earth years.

For now, the planet is officially the unromantic 2003 UB313.