Chariklo’s Rings Are Evolving

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By Kimberly M. S. Cartier, Eos/AGU. 

Excerpt: Tiny asteroid Chariklo, floating through the void between Saturn and Uranus, boasts two rings. It’s the first asteroid found to have them, and their existence took astronomers by surprise when they were spotted in 2013. ...“The opacity of the outer ring is now lower than in the previous observations, but also the opacity of the inner ring was stronger,” said Pablo Santos-Sanz, an astrophysicist at Instituto de Astrofísica de Andalucía in Granada, Spain, and lead researcher on the discovery. ...Chariklo is a Centaur asteroid, meaning it orbits the Sun in the space between the giant planets. It’s 302 kilometers (108 miles) across, is not very spherical, and orbits about 2.3 billion kilometers (1.5 billion miles) from the Sun. In 2013, Chariklo passed between earthbound observers and a distant star, an alignment called stellar occultation. Astronomers saw that the star’s light dimmed twice before Chariklo obscured the star and twice again after Chariklo passed by, revealing the presence of two thin rings orbiting the asteroid. That made Chariklo only the fifth solar system object, the first besides the four giant planets, discovered to have rings. Later observations revealed that the rings are thin, sharply defined, and separated by a mere 14 kilometers (8.7 miles). Other measurements suggest they may contain water ice.... 

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