The discovery is putting into question everything astronomers believed about ring systems.
Astronomers from the University of Sheffield discovered a new ring system around a dwarf planet on the edge of the Solar System, according to a press release. The discovery calls into question current theories about how ring systems are formed since the ring system orbits much further out than is typical for other ring systems.
Around a dwarf planet
The ring system is located around a dwarf planet named Quaoar, which is approximately half the size of Pluto and orbits the Sun beyond Neptune.
The astronomers spotted the ring system by using HiPERCAM - an extremely sensitive high-speed camera developed by scientists at the University of Sheffield, which is mounted on the world's largest optical telescope, the 10.4-meter diameter Gran Telescopio Canarias (GTC) on La Palma.
The rings cannot be seen directly in an image, so the discovery had to be made by observing an occultation when the light from a background star was blocked by Quaoar as it orbits the Sun.
The event is hailed as a breakthrough because ring systems are relatively rare in the Solar System, and all currently known ring systems are able to survive because they orbit close to the parent body, so tidal forces prevent the ring material from accreting and forming moons. In 2018, NASA even reported that Saturn's rings seemed to be disappearing.
Seven planetary radii
However, the ring system around Quaoar lies at a distance of over seven planetary radii - twice as far out as what was previously thought to be the maximum radius according to the so-called "Roche limit," which is the outer limit of where ring systems were thought to be able to survive.
"It was unexpected to discover this new ring system in our Solar System, and it was doubly unexpected to find the rings so far out from Quaoar, challenging our previous notions of how such rings form. The use of our high-speed camera - HiPERCAM - was key to this discovery as the event lasted less than one minute, and the rings are too small and faint to see in a direct image," said professor Vik Dhillon, co-author of the study from the University of Sheffield's Department of Physics and Astronomy.
"Everyone learns about Saturn's magnificent rings when they're a child, so hopefully, this new finding will provide further insight into how they came to be."
The study saw the cooperation of 59 academics from all over the world, led by the Federal University of Rio de Janeiro in Brazil.