'Impossible' New Ring System Discovered at the Edge of the Solar System
Astronomers are puzzled by a ring around the icy dwarf planet Quaoar that is much farther from its parent body than thought possible
By Robert Lea, LiveScience on February 11, 2023
An artist's impression of the dwarf planet Quaoar, located beyond Neptune. Credit: ESA, CC BY-SA 3.0 IGO
Astronomers have discovered an entirely new ring system within the solar system, and it's located at such a great distance from its dwarf planet parent that it should be impossible.
The ring surrounds Quaoar, which is around half the size of Pluto and located beyond Neptune. It is only the third ring to be found around a minor planet and the seventh ring system in the solar system, with the most famous and well-studied rings surrounding the giant planets Saturn, Jupiter, Neptune and Uranus.
"The six [previously known] planets with ring systems all have rings which are quite close to the surface of the planet. So this really challenges our ring formation theories," study co-author Vik Dhillon, a professor of physics and astronomy at the University of Sheffield in England, told Live Science. "It was previously thought to be impossible to have rings that far out, so in a nutshell, the ring of Quaoar is a real challenge to explain theoretically."
The ring system is located at a distance of seven planetary radii away from Quaoar (that is, seven times Quaoar's radius), which is twice as far out as the theoretical maximum limit for a ring system, known as the Roche limit. For comparison, the main part of Saturn's rings sits at just three planetary radii from the gas giant.
More:
https://www.scientificamerican.com/article/impossible-new-ring-system-discovered-at-the-edge-of-the-solar-system/
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