Free Astronomy Magazine November-December 2020

16 NOVEMBER-DECEMBER 2020 SPACE CHRONICLES by ESO A planet - forming disc torn apart by its three central stars A team of astronomers have identified the first direct ev- idence that groups of stars can tear apart their planet-forming disc, leaving it warped and with tilted rings. This new research sug- gests exotic planets, not unlike Tatooine in Star Wars, may form in inclined rings in bent discs around multiple stars. The results were made possible thanks to observations with the European Southern Observa- tory’s Very Large Telescope (ESO’s VLT) and the Atacama Large Millime- ter/submillimeter Array (ALMA). Our Solar System is remarkably flat, with the planets all orbiting in the same plane. But this is not always the case, especially for planet-form- ing discs around multiple stars, like the object of the new study: GW Ori- onis. This system, located just over 1300 light-years away in the constel- lation of Orion, has three stars and a deformed, broken-apart disc sur- rounding them. “Our images reveal an extreme case where the disc is not flat at all, but is warped and has a misaligned ring that has broken away from the disc,” says Stefan Kraus, a professor of astrophysics at the University of Exeter in the UK who led the re- search published in the journal Sci- ence . The misaligned ring is located in the inner part of the disc, close to the three stars.