The upside-down orbits of a multi-planetary system

The perpendicular orbits of the HD3167 planets: jewels of the Pisces constellation. Gilliane Devidal - Astronomers led by the UNIGE have discovered exoplanets that orbit in planes at 90 degrees from each other. When planets form, they usually continue their orbital evolution in the equatorial plane of their star. However, an international team, led by astronomers from the University of Geneva , Switzerland, has discovered that the exoplanets of a star in the constellation Pisces orbit in planes perpendicular to each other, with the innermost planet the only one still orbiting in the equatorial plane. Why so? This radically different configuration from our solar system could be due to the influence of a distant companion of the star that is still unknown. This study, to be read in the journal Astronomy & Astrophysics , was made possible by the extreme precision achieved by ESPRESSO and CHEOPS, two instruments whose development was led by Switzerland. Theories of the origin of planetary systems predict that planets form in the equatorial plane of their star and continue to evolve there, unless disturbed by special events.