Using observations from NASA’s Cassini spacecraft, a team of French scientists were able to identify possible positions for the recently proposed Planet Nine.
On January 20th of this year, astronomers from Cal-tech announced strong evidence for a ninth planet about 10 times the mass of Earth, in the far-outer reaches of our solar system. The proposed “Planet Nine” was inferred by analyzing the strange orbits of smaller known objects beyond Pluto.
A team of french scientists took it one step further using the Cassini spacecraft, which primarily explores the Saturn system. Since 2003, scientists have been developing a system with Cassini data, known as the INPOP planetary ephemerides, that calculates the motion of the planets in our solar system with extreme accuracy. Researchers had the idea to explore the systems data to see if planet nine had caused perturbations in Saturn’s orbit.
The study, published in the journal Astronomy & Astrophysics, shows that depending on the position of the planet from its perihelion (orbits closest point to the sun), the ninth planet induces perturbations in the orbit of Saturn. The results allowed scientists to exclude areas of direction and narrow down the orbital characteristics of the inferred planet.
According to the team, the most plausible position for planet nine is at an angle from perihelion between 104 ° and 134 °, with a maximum probability for 117 °. Simulations show the addition of a Planet Nine under these perimeters improves the model prediction, reducing the differences between the calculations and Cassini data.
Researchers point out that the ninth planet can only be confirmed by direct observations – the study will likely be an important tool for astronomers on the hunt.