All four of our solar system’s gas giants sport rings, the gaudiest of course being those of Saturn. But they’re not alone. A body called 10199 Chariklo orbits between Saturn and Uranus. And a close examination has revealed that it too has rings.
Chariklo is the largest of a class of objects called centaurs, which have characteristics of both asteroids and comets. They can display glowing comas if they’re kicked in close to the sun.
The European Southern Observatory’s La Silla Observatory in Chile and other South American telescopes found that Chariklo hosts two dense circular rings made of ice and pebbles (see video here). They lie roughly 400 kilometers out from Chariklo, itself just 250 kilometers wide. The discovery is in the journal Nature. [F. Braga-Ribas et al, A ring system detected around the Centaur (10199) Chariklo]
One theory behind the unusual situation is that another body crashed into Chariklo, and the material ejected by the collision coalesced into the rings. Chariklo could eventually lose its special status if the rings gather up and form a moon. Asteroids with moons are commonplace. But for now, this ringed Centaur is truly a horse of a different color.
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[Scientific American is part of Nature Publishing Group.]