The source of Saturn's G ring.
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 approximately 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.
Hedman
Matthew M
MM
Department of Astronomy, Cornell University, Ithaca, NY 14853, USA. mmhedman@astro.cornell.edu
Burns
Joseph A
JA
Tiscareno
Matthew S
MS
Porco
Carolyn C
CC
Jones
Geraint H
GH
Roussos
Elias
E
Krupp
Norbert
N
Paranicas
Chris
C
Kempf
Sascha
S