Threedimensional hydrodynamical simulations of offcentre collisions between a white dwarf and a mainsequence star
Abstract
A finite difference code based on the piecewise parabolic method is used here to study offcenter collisions between an 0.5 solar mass mainsequence star (MSS) modeled by a polytrope index of 1.5 and an 0.5 solar mass white dwarf (WD) modeled by a pointmass potential. At small impact parameters, the MSS is totally disrupted, its matter eventually settling around the WD, while for large impact parameters the MSS is only slightly elongated. The amount of mass becoming unbound due to the collision is estimated to be roughly 15 percent. The expansion of the shockheated gas is spherically symmetric. The maximum temperatures reached during the collision are so low that the nuclear energy production is negligible.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 November 1990
 Bibcode:
 1990A&A...238..116R
 Keywords:

 Computational Astrophysics;
 Hydrodynamic Equations;
 Main Sequence Stars;
 Three Dimensional Models;
 White Dwarf Stars;
 Angular Momentum;
 Collisions;
 Fast Fourier Transformations;
 Finite Difference Theory;
 Shock Heating;
 Stellar Envelopes;
 Stellar Mass;
 Astrophysics