Astronomers Find a Ring Around Dwarf Planet Quaoar

Astronomers have found a ring around a dwarf planet, located in the Kuiper Belt at the solar system’s edge, called Quaoar. The ring, however, is positioned much further away from the planet than is usual and defies theoretical explanations. The study, ‘A dense ring of the trans-Neptunian object Quaoar outside its Roche limit’, has been done by Bruno Morgado of the Federal University of Rio de Janeiro (Brazil), Bruno Sicardy of the Paris Observatory, and others. The ring lies far away from the Roche limit — a mathematically determined distance beyond which rings aren’t supposed to exist. The researchers detected the ring with the help of a phenomenon called stellar occultation. A stellar occultation occurs when, as seen from Earth, a bright star passes behind a planet. This allows astronomers or anybody on Earth to observe the sharp silhouette of the planet for a brief period of time. The team involved in the latest study examined Quaoar for around three years, between 2018 and 2021, through Earth-based and space-based telescopes. The most intriguing part of the findings is the distance between Quaoar and its ring. Located 2,500 miles away from the dwarf planet, the ring is around 1,400 miles further away from the Roche limit. It is named after the French astronomer Édouard Roche, who discovered the limit in 1848. As of now, nobody exactly knows how Quaoar’s ring has managed to remain stable at such a distance from the Roche limit. Astronomers believe the new study points to the possibility of discovering more rings around smaller planets like Quaoar in the outer solar system, which might expand our understanding of planetary ring systems.