In the past rings, such as those on Saturn, had only been observed on planets; new observations found two thin rings around an orbiting asteroid.
"We weren't looking for a ring and didn't think small bodies like Chariklo had them at all, so the discovery - and the amazing amount of detail we saw in the system - came as a complete surprise!" lead author Felipe Braga-Ribas pf Observatório Nacional/MCTI, Rio de Janeiro, Brazil, said in an European Southern Observatory news release.
The distant minor planet, dubbed Chariklo, is part of a class known as Centaurs which orbit between Saturn and Uranus. The researchers observed the star passing in front of the star UCAC4 248-108672.
The researchers observed two dips in the light cast off by the star, suggesting that something must be blocking it. The researchers observed the asteroid from several different sites; by making these observations the team could determine the properties of both the object and its rings.
"For me, it was quite amazing to [realize] that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings," team member Uffe Gråe Jørgensen of Niels Bohr Institute, University of Copenhagen, Denmark, said in the news release. "I try to imagine how it would be to stand on the surface of this icy object - small enough that a fast sports car could reach escape velocity and drive off into space - and stare up at a 20-[kilometer] wide ring system [1,000] times closer than the Moon." The object itself is only about 250 kilometers in diameter.
Researchers believe Chariklo's rings were formed from debris left over after a collision.
"So, as well as the rings, it's likely that Chariklo has at least one small moon still waiting to be discovered,"Felipe Braga Ribas said in the news release.
The rings could one day lead to the formation of a small moon; this idea could help researchers gain insight into how our own moon formed.
