Two-body model for the spatial distribution of dust ejected from an atmosphereless body

We present a model for the configuration of noninteracting material that is ejected in a continuous manner from an atmosphereless gravitating body for a given distribution of sources. The model is applicable to material on bound or unbound trajectories and to steady and nonsteady modes of ejection. For a jet that is inclined to the surface normal, we related the distributions of ejection direction, velocity, and size to the phase-space number density at the distance from the source body. Integrating over velocity space, we obtained an expression from which we inferred the density, flux, or optical depth of the ejected material. As examples for the application of the code, we calculate profiles of the dust density in the Enceladus plume, the pattern of mass deposition rates around a plume on Europa, and images of optical depth following the nonstationary emission of material from a volcano on Io. We make the source code of a Fortran-95 implementation of the model freely available.