;
• Burns, Joseph A.
;
• Tiscareno, Matthew S.
;
• Porco, Carolyn C.
;
• Jones, Geraint H.
;
• Roussos, Elias
;
• Krupp, Norbert
;
• Paranicas, Chris
;
• Kempf, Sascha

Abstract

The origin of Saturn’s narrow G ring has been unclear. We show that it contains a bright arc located 167,495.6 ± 1.3 km from Saturn’s center. This longitudinally localized material is trapped in a 7:6 corotation eccentricity resonance with the satellite Mimas. The cameras aboard the Cassini spacecraft mainly observe small (1 to 10 micrometers) dust grains in this region, but a sharp decrease in the flux of energetic electrons measured near this arc requires that it also contain larger (centimeter- to meter-sized) bodies whose total mass is equivalent to that of a ~100-meter-wide ice-rich moonlet. Collisions into these bodies may generate dust, which subsequently drifts outward to populate the rest of the G ring. Thus, the entire G ring could be derived from an arc of debris held in a resonance with Mimas.