A computationally efficient semi-analytical model for the dust environment of comets and asteroids

Aims. We present a model for the distribution of dust ejected by asteroids and comets. Our model incorporates the effects of solar gravity and radiation pressure. In specific cases it can also account for additional forces and the re-impacts of ejected dust onto the source body. Methods. The number density of dust at a given point in space was computed as the sum of contributions from a set of point sources placed along a given trajectory, ejecting dust in a temporal sequence that approximates the motion of the source body. The dust ejection from each source was modeled using continuous distributions of the dynamical parameters the dust grains have at ejection. We developed three methods to solve for the dust number density from a single point source that differ in complexity and applicability. Results. We applied the model to investigate the dust environment of the near-Earth asteroid Phaethon, and estimated the number of dust grains that will be observed by the dust detector on the flyby of the forthcoming DESTINY+ mission by JAXA. Additionally, as an illustrative example, we reconstructed an image of comet C/1996 B2 (Hyakutake) to demonstrate the details of working with the model. The implementation of our model, verified with a comparison to independent software, is freely available as a Fortran-95 package, DUDI-heliocentric.