US astronomers announced last month they may have found a ninth planet beyond Neptune, but conceded they had no idea where on an estimated 10,000-20,000-year orbit it might be.

On Tuesday, a French science quartet said they have narrowed the search area.

By studying data from NASA's Cassini spacecraft orbiting Saturn, the seventh planet from the Sun, they could exclude two zones, the team wrote in the journal Astronomy and Astrophysics.