Modeling of the inner atmosphere of comets with aspheric nucleus of “apple” type

Mathematical modeling of two-dimensional steady flows in the inner gas atmosphere of comets with nucleus of “apple” type was carried out. The “apple”-type nucleus have a large completely sunlit cavity on day side. Two methods were used for the modeling: gasdynamic approach of Navier–Stokes and the Direct simulation Monte-Carlo method. The comparison of the results obtained by these methods have shown fairly good agreement. A flow in the cavity was investigated in details. A possibility of formation in the cavity of closed regions with returning flow and complex gasdynamic structure is demonstrated.