Free Astronomy Magazine September-October 2021

16 SEPTEMBER-OCTOBER 2021 ASTRO PUBLISHING The first clear image of an exomoon-forming disc by ESO - Bárbara Ferreira T his image, taken with the Ata- cama Large Millimeter/submil- limeter Array (ALMA), in which ESO is a partner, shows wide (left) and close-up (right) views of the moon- forming disc surrounding PDS 70c, a young Jupiter-like planet nearly 400 light-years away. The close-up view shows PDS 70c and its circum- planetary disc centre-front, with the larger circumstellar ring-like disc taking up most of the right- hand side of the image. The star PDS 70 is at the centre of the wide- view image on the left. [ALMA (ESO/NAOJ/NRAO)/Benisty et al.] U sing the Atacama Large Mil- limetre/submillimeter Array (ALMA), in which the Euro- pean Southern Observatory (ESO) is a partner, astronomers have unam- biguously detected the presence of a disc around a planet outside our Solar System for the first time. The observations will shed new light on how moons and planets form in young stellar systems. “Our work presents a clear detection of a disc in which satellites could be forming,” says Myriam Benisty, a researcher at the University of Grenoble, France, and at the University of Chile, who led the new research published in The Astrophysical Journal Letters .