New rings found on the edge of our Solar System

A team of researchers led by the University of Sheffield in the UK has recently discovered a new ring system on the edge of our Solar System. These rings – located around Quaoar, a Pluto-sized dwarf planet orbiting beyond Neptune – are unique, orbiting much further away from the planet than Saturn’s rings, for instance, and thus posing challenges to current ring formation theories.

The experts discovered the rings by using HiPERCAM, an extremely sensitive high-speed camera mounted on Gran Telescopio Canarias (GTC), the world’s largest telescope, with a diameter of 10.4 meters. Since the rings are too small and faint to observe directly, the researchers detected them by noticing an “occultation” – a phenomenon in which the light from a background star was blocked by Quaoar as it orbited the Sun. Although this event lasted less than a minute, it was unexpectedly preceded and followed by two dips in light, indicating the presence of a ring system around this planet.

Such ring systems are quite rare in our Solar System, being present only around a handful of planets, including Saturn, Jupiter, Uranus, Neptune, Chariklo, and Haumea. All these previously detected rings are able to survive due to the fact that they orbit close to their planets, so tidal forces prevent the ring material from accreting and forming moons. By contrast, the newly discovered ring lies at a distance of more than seven planetary radii – twice as far than what scientists thought to be the maximum radius where rings can form. Thus, this finding may force experts rethink current theories of ring formation.

“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 study co-author Vik Dhillon, an astrophysicist at Sheffield.

“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 is published in the journal Nature.

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By Andrei Ionescu, Earth.com Staff Writer

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