Distant Stars Spotlight Mini Moons in Saturn’s Rings

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By Katherine Kornei, Eos/AGU.

Excerpt: Using data from the Cassini spacecraft, researchers studying one of the rings recently uncovered gaps just a few tens of meters wide that they believe surround unseen mini moonlets. ...In addition to capturing more than 450,000 images of the Saturnian system, the spacecraft inadvertently tracked distant stars poking through Saturn’s rings. ...The researchers spotted dozens of places in Saturn’s C ring—one of its innermost rings—that appeared to be 100% transparent. ...Their elongated geometry was a tip-off to their potential identity—similarly shaped structures, albeit much larger, have been spotted in the outer regions of Saturn’s A ring. Known as propellers [resembling airplane propellers], those features are big enough to show up in Cassini imagery rather than just occultation data, Jerousek said. ...Scientists believe that propellers exist because of unseen moonlets measuring, at most, several hundred meters in diameter.... 

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