Capture of Interplanetary and Interstellar Dust by the Jovian Magnetosphere

Abstract

Interplanetary and interstellar dust grains entering Jupiter's magnetosphere form a detectable diffuse faint ring of exogenic material. This ring is composed of particles in the size range of 0.5 to 1.5 micrometers on retrograde and prograde orbits in a 4:1 ratio, with semimajor axes 3 < a < 20 jovian radii, eccentricities 0.1 < e < 0.3, and inclinations i ≲ 20 degrees or i ≳ 160 degrees. The size range and the orbital characteristics are consistent with in situ detections of micrometer-sized grains by the Galileo dust detector, and the measured rates match the number densities predicted from numerical trajectory integrations.