Mystery as Pluto-sized planet is found to have an 'unusual' ring of debris ... trends now
Astronomers have spotted a Saturn-like ring of debris around a Pluto-sized dwarf planet that they did not think was possible.
The researchers said their discovery defies the current understanding of where such rings can form — because it is much further away from the small distant world than current scientific understanding would allow.
Surrounding the dwarf planet Quaoar, which sits beyond Neptune, the 'unusual' ring calls into question how such systems form.
'We have observed a ring that shouldn't be there,' said Bruno Morgado at the Federal University of Rio de Janeiro.
The distance of the ring from Quaoar places it in a location where scientists believe particles should readily come together around a celestial body to form a moon, rather than remain as separate components in a disk of ring material.
'Unusual': Astronomers have spotted a Saturn-like ring of debris around a Pluto-sized dwarf planet that they did not think was possible. Pictured is an artist's impression of Quaoar's ring
Ring systems are relatively rare in the Solar System, and as well as those around Saturn, Jupiter, Uranus and Neptune, only two minor planets possess rings – Chariklo and Haumea.
All of the previously known ring systems are able to survive because they orbit close to the parent body.
According to the astronomers, what makes the ring system around Quaoar remarkable is that it lies at a distance of over seven planetary radii – twice as far out as what was previously thought to be the maximum limit, which is the outer limits of where ring systems were thought to be able to survive.
Therefore the discovery has forced a rethink on theories of ring formation.
The discovery was made by an international team of astronomers using HiPERCAM – an extremely sensitive high-speed camera developed by scientists at the University of Sheffield.
It is mounted on the world's largest optical telescope, the 10.4 metre diameter Gran Telescopio Canarias on La Palma.
Because the rings are too faint to see directly in an image, the discovery was made by observing an occultation – when the light from a background star was blocked by Quaoar