'10th planet' has moon companion

BBC NEWS: "The astronomers who in July announced the discovery of a '10th planet' in our Solar System say the object has a moon. The new development comes as a result of observations made with the Keck Observatory on Mauna Kea, Hawaii. Michael Brown, from the California Institute of Technology, US, says the find will help his team make a better determination of the new planet's mass. Currently, the planet has been dubbed Xena; the moon will be called Gabrielle until official names are agreed. Both 'codenames' come from characters in a US TV series, Xena: Warrior Princess. 'Since the day we discovered Xena, the big question has been whether or not it has a moon,' Professor Brown said in a statement. 'Having a moon is just inherently cool - and it is something that most self-respecting planets have, so it is good to see that this one does, too.'"