Technology & Science

Chiron centaur may have ring, scientists say

The minor planet Chiron may not be a household name like Saturn, but it might just have a ring to it. Scientists observing the centaur believe they have detected a circulating disc of debris around the minor planet.

'It's turning out things are quite active,' MIT researcher says of centaurs

An artist's impression shows what the rings around the remote asteroid-like object Chariklo might look like. Scientists now believe another minor planet, Chiron, may also have a ring. (L. Calcada/M. Kornmesser/Nick Risinger/ESO)

The minor planet Chiron may not be a household name like Saturn, but it might just have a ring to it.

Scientists observing the centaur — a class of small, hybrid celestial bodies with characteristics of asteroids as well as comets — believe they have detected a circulating disc of debris around the minor planet.

If true, Chiron would join Chariklo as the second centaur with such a halo. It would also become only the sixth ringed body in Earth's solar system.

Scientists only discovered Chariklo's double-ring system as recently as last year. It was a surprising find, as scientists presumed the asteroid-like objects were more or less dormant.

"It's interesting, because Chiron is a centaur — part of that middle section of the solar system, between Jupiter and Pluto, where we originally weren't thinking things would be active," said Amanda Bosh , a lecturer with the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology.

"It's turning out things are quite active."

Ring, shell or jets?

Both Chiron's and Chariklo's diameters are only about 246 kilometres. Previously, rings were identified on the giant planets in our solar system such as Saturn, Jupiter, Uranus and Neptune.

Chariklo became the fifth ringed body last year.

The possibility of a halo orbiting Chiron came to light after researchers with the Massachusetts Institute of Technology studied a November 2011 "stellar occultation," an event in which light from a star was blocked by an intervening body.

In this case, light effects created when Chiron drifted in front of a bright star seemed to reveal a shadow indicating a mysterious disk.

Scientists believe that could signify a ring system, a circular "shell" of gas and dust, or jets of material — possibly ice heated by the sunlight — shooting vapour off the surface.

Bosh and her colleagues have published their findings in the journal Icarus.

According to the researchers, our solar system is estimated to have about 44,000 centaurs.

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