Dynamics of an Affine Star Model in a Black Hole Tidal Field

Consequences of a model are considered, in which it was recently shown that the tidal disruption of a star moving in a deeply plunging orbit in the field of a large black hole such as may occur in an active galactic nucleus can most conveniently be studied in a first approximation using a simple affine star model. Explicit results are given of numerical integration of the dynamic equations of motion of the affine star model in various cases that have not been examined in detail before, concentrating on the regime prior to the release of dynamically significant nuclear energy, where the model can be expected to be most reliable. In addition to studies aimed at improved realism in the treatment of medium-mass and higher mass stars on the basis of the neutral affine analog of Eddington's standard model (using a simple treatment of the separate contributions of gas and radiation pressure), the work also includes studies of the incompressible limit, aimed at completing the classical work on this subject, and also studies the effect of (artificially high) viscous dissipation, aimed at comparison with the first crude hydrodynamic investigations, in which artificial dissipative effects are important.