Friday, 28 March 2014 | MYT 7:00 AM

Chariklo, first asteroid discovered to have rings like Saturn

It's not just Saturn and the giant gas planets of the solar system that bear rings. For the first time, rings have been found around an asteroid.

The asteroid, known as 10199 Chariklo, is more than a billion kilometres from Earth, circling the sun in an orbit between Saturn and Uranus.

On June 3 last year, astronomers at seven different locations in Chile, Brazil, Uruguay and Argentina were standing by to observe the asteroid as it passed in front of star, relative to the telescopes’ lines of sight.

They hoped the dips in starlight, caused by the asteroid passing in front of the star, would reveal details of the 248km asteroid’s size and shape. They ended up with much more.

An artist's rendering of Chariklo with its rings. – Wikipedia/ESO/L Calçada/M Kornmesser/Nick Risinger.

Analysing flickers of light during the occultation revealed two dense rings circling Chariklo. Previously, only the giant planets – Saturn, Jupiter, Uranus and Neptune – were known to have rings.

“We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all,” lead astronomer Felipe Braga-Ribas, with Brazil’s National Observatory in Rio de Janeiro, said. “The discovery... came as a complete surprise.”

Chariklo’s rings have crisp edges, a feature typically caused by the gravitational effects of a small embedded moon or moons. Chariklo’s inner ring is 7km wide and the outer ring is 3km wide. The bands are separated by a 9km wide gap.

“It’s likely that Chariklo has at least one small moon still waiting to be discovered,” Braga-Ribas said.

Chariklo compared to Pluto and Earth's moon, based on mean radius. – Wikipedia/Interchange88/QuantumShadow.

“It was quite amazing to realise that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings,” astronomer Uffe Grae Jorgensen, with the University of Copenhagen in Denmark, said.

The origin of the rings is not known, but scientists suspect they formed after another body crashed into Chariklo, forming a debris disk of icy particles. The research is published in this week’s issue of the journal Nature. – Reuters

Tags / Keywords: Lifestyle , Science Technology , Science , Astronomy , asteroid , planetary rings , Chariklo , Saturn , Uranus , Neptune , Jupiter , solar system


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