Dust Grains around Jupiter—The Observations of the Galileo Dust Detector

Abstract We analyze the data of the Galileo dust detector system (DDS) with respect to micrometer-sized dust grains in the inner jovian system. The analysis of these data requires an in-depth modeling because an exact determination of the orbits of individual particles directly from the data is not possible. We find that a ring of prograde particles with masses between 10 −12 and 10 −11 g is compatible with the data. The number density in the region around Europa's orbit is at least 4×10 −13 cm −3 . The strongest impacts observed, however, are caused by a smaller population of particles in the same mass range but on retrograde orbits. These particles are probably captured interplanetary or interstellar grains (J. E. Colwell et al. 1998, Science 280 , 88). Possible sources for the prograde dust are the Galilean satellites, especially Europa and Io.