A model of multigeneration neutrals in cometary comae

The spatial distribution of neutral species in the outer coma of a comet is described using a modified version of the fountain model. This model accounts for neutrals that are produced in multiple generations after release from the nucleus (or production in the collision zone of the inner coma) by an iterative application of the fountain model. A preliminary description of the model is given; however, results are presented in a future paper. Suitable applications of the model include the following: (1) distributed coma sources of neutral gas phase species from anisotropic dust emission; (2) the description of cometary comae at large heliocentric distances; and (3) day/night asymmetry of gas production from the nucleus.