Modelling the circumstellar coma of comets: objectives, methods and recent results
Publication date: 01 June 1999
Authors: Crifo, J.F. & Rodionov, A.V.
Journal: Planetary and Space Science
Copyright: Elsevier ScienceWe investigate whether the modelling of the immediate vicinity of an active nucleus -currently unobservable- can, as the modelling of the outer, observable coma, be based on unrealistic simple assumptions such as those of nucleus and dust grains sphericity. We point out the inconsistency of models based on such assumptions, which, to manage compatibility with the observations, have to introduce additional assumptions that conflict with the previous ones, such as the existence of active areas of the nucleus. We argue that, while the outer coma models being phenomenological in nature, can perhaps tolerate such inconsistencies, the circumnuclear coma models must be predictive, having to obviate the lack of observational data, and therefore must exclude implausible and ad hoc assumptions, and advocate only well-understood physical processes and duly validated modelling methods. We describe the first steps of development of a predictive circumnuclear coma model, and present a set of results obtained with parameters fitted to comet 46P/Wirtanen, the target of the Rosetta mission, but of a quite general significance.