Cassini/Cosmic Dust Analyzer in situ dust measurements between Jupiter and Saturn

Abstract

We report an analysis of the Cosmic Dust Analyzer data obtained during the interplanetary cruise of the Cassini spacecraft between Jupiter and Saturn. The data cover the time period between the Jupiter flyby and the Saturn orbit insertion. Seventeen dust particles on bound and unbound (hyperbolic) orbits were also detected, with sizes in the submicrometer to the micrometer range. Our measurements are compared with the Pioneer dust data obtained 30 years ago and model predictions. Particles on bound orbits have low eccentricities and low inclinations. Possible sources are short-period Jupiter family comets and circumsolar dust. The impactors on hyperbolic orbits were identified as being most likely interstellar dust (ISD) grains with a radius of ≈0.4 μm. The corresponding flux of ≈2 × 10^-5 m^-2 s^-1 is in a very good agreement with the ISD flux measurements performed by the Ulysses spacecraft over the same time period.