In a recent paper in the Proceedings of the National Academy of Sciences a group of researchers led by Maria Hjorth and Simon Albrecht from the Stellar Astrophysics Centre, Aarhus University, have published the discovery of a special exoplanetary system in which two exoplanets are orbiting backward around their star. This surprising orbital architecture was caused by the protoplanetary disk in which the two planets formed being tilted by the second star in this system.
Click here for original story, A backward-spinning star with two coplanar orbiting planets in a multi-stellar system
Source: Phys.org