"A rogue planet could have been ejected from our solar system and perturbed their orbits," says astronomer Scott Sheppard of the Carnegie Institution for Science in Washington, D.C., who coauthored the discovery report in the journal Nature. "Definitely, it could still be out there."
The journal article reports on what they know for a fact. Another planet on an unusual orbit is speculation for now, so I'm not surprised they didn't mention it - although I hope that as they gather more data they'll be able to infer its location and see it block stars or somesuch, if it exists.
The journal article reports on what they know for a fact. Another planet on an unusual orbit is speculation for now, so I'm not surprised they didn't mention it - although I hope that as they gather more data they'll be able to infer its location and see it block stars or somesuch, if it exists.