Does Saturn have rings outside 10 R_s?

Abstract

Vasundhara et al.¹ and Mahra et al.² have recently reported detections of new saturnian ring systems near 12.5 and 19.5 Saturn radii (R_s), respectively. Lazarus et al.³ have previously suggested that one or more tenuous rings may exist between 14 and 19 R_S, based on observations of unexplained drops in low-energy plasma ion densities in this region of the magnetosphere by Pioneer 11 and Voyagers 1 and 2. However, Baron and Elliot⁴ have placed a stringent upper limit on the I-band brightness of any material in the region 10–36 R_s west of Saturn. Here we review the Voyagerion and electron data in the energy range 30–1,000 keV as measured by the Low Energy Charged Particle (LECP) experiment. There is no convincing evidence for ring matter outside 10 R_s in these data. Features in the charged particle fluxes in these regions are more readily explained by temporal variations and/or spatial structure unrelated to ring matter, such as the mantle on the dayside⁵ and/or detached plasma sheets⁶.