The Jovian ring

Abstract

The results of further measurements of the Jovian ring system are presented. The system has three major components: the bright ring, the faint sheet, and the out‐of‐plane halo. The bright ring has an outer radius of 1.81±0.01 R J , an inner radius 1.72±0.01 R J , an eccentricity not greater than 0.003 and a normal optical depth 3 × 10 −5 . The faint sheet extends from the inner edge of the bright ring to the surface of Jupiter. Its optical depth is approximately 7 × 10 −6 . Three arguments are presented to show that a halo of material envelops the above two rings and extends 10 4 km above the ring plane. A simple model is invoked to account for the halo by means of interactions between the Jovian magnetic field and charged ring particles less than 0.5 µm in diameter. The source of small particles is probably within the bright ring itself and may be due to micrometeorite impact into larger ring bodies. Small particles evolve in towards Jupiter under Poynting Robertson and other drag forces. The outer edge of the ring system is defined by the satellite 1979J1.