Spatial and mass distribution of low-mass dust particles (m < 10 −10 g) in comet P/Halley’s coma

Abstract

The spatial distribution of cometary dust particles in the mass range ~10−10 to ~3 10−17g was obtained with the plasma impact detectors SP-1 on Vega-1 and Vega-2. The mass spectrum continues to rise in the range 10−14–3 10−17g. The evolution of the mass spectrum with distance suggests radiation pressure separation and some other effects. Several dust shells are easily distinguished by spatial gradients and by different properties of the grains. The spatial mass dispersion in the prominent jet observed on Vega-2 is used to evaluate the rotation of the nucleus and to calculate the velocity dispersion of the dust.