Where could be the “ninth planet” US researchers believe they have discovered through mathematical models? Of French astronomers have managed to clarify the directions that guide the telescopes to try to find.

“Given all that we know about the movements of the planets of the solar system, our work allows us to say that it is possible but it is not anywhere,” said Jacques Laskar AFP astronomer at the Paris Observatory, who published a study with Agnes Fienga, the Observatory of the Cote d’Azur (south of France).

January 20, Konstantin Batygin and Mike Brown of the California Institute of Technology (Caltec) created a stir by announcing that a “ninth planet” very large and very distant, could exist in our solar system. They have relied on mathematical models and computer simulations.

With a mass about ten times that of the Earth, this planet would be in an orbit twenty times farther than Neptune. Very slow, it would put between 10,000 and 20,000 years to complete turn around the sun.

The French researchers had the idea of ​​adding this ninth still in their virtual world INPOP model of the solar system.

“We assumed that there was indeed a planet in orbit proposed by the Americans and we looked at the influence it would have on other planets,” says Laskar whose work is published in Astronomy & Astrophysics Letters.

“With Cassini accompanying Saturn since 2004, we know the Earth-Saturn distance 100 meters around for over ten years. We looked at how this distance would be changed by the existence of the” ninth planet “, in due to the gravitational attraction between the heavenly bodies, it adds research director at the CNRS (National scientific research Centre).

– Work ‘halved’ –

Teams of two astronomers have identified two areas where it is possible that the planet is because its effects would be incompatible with the data from the Cassini spacecraft.

Before the study, the scientific community does not know where to turn his eyes to try to locate.”Here, we remove half of the possible directions,” said Mr Laskar. “We divide the work by two.”

The study also said that “nothing prevents the existence of the ninth planet in all other directions.”

There is even a place where his presence could be “likely” because when this planet when we add the model fits better with the observations, says Mr. Laskar remains cautious, however. “I would not put my life on it,” he said.

The researchers worked with data from the Cassini probe up to 2014.

“These results could be improved if Cassini was extended until 2020,” says Laskar. “This would still halve the zone” where to look.

For now, it is expected that the probe Cassini, made by NASA in collaboration with the European Space Agency (ESA), to end its mission by diving on Saturn in 2017. But some scientists hope the probe will obtain the necessary financing its extension.

If amateur astronomers have no hope of identifying the “ninth planet” too far, many researchers are beginning to mobilize to find it visually, says Francis Rocard, head of exploration programs in the solar system to the French space agency CNES.

“Because of its low light, you can use only the largest telescopes such as the VLT in Chile or the Hubble Space Telescope,” he says on the blog CNES. But it would be “more effective” to? Use instruments having a wide field of vision as the Subaru telescope in Hawaii.

“It will take time, maybe five years, because it is necessary to compare the views of the sky spaced one to several years to confirm that? Object is on? Orbit predicted” by US scientists says Mr. Rocard .