This actually isn't the first 10th planet that they've run across. Anyone remember sedna? The difference here is that sedna was tiny even compared to pluto while the new find is something like 3x as big based on the latest estimates. The nerds who found it have nicknamed it Xena. Apparently they can't officially give it a name other than that alphabet soup until it's officially designated as something, either a planet or an asteroid or whatever.
It seems the new planet has a moon that's been dubbed Gabrielle for Xena's sidekick on the old tv show. Nerds....sometimes I wonder if they just wait their entire lives to be able to do something this geeky. Of course, the nicknames will never fly even if they do get officially added to the solar system. We'll probaly have to go and pull another roman god without a planet named after him or her out of the closet.