FRONTIERS IN COMPUTATIONAL ASTROPHYSICS

Particle and Flames in Radiative and Magnetic Flows

October 11-15, 2010
Lyon, France

Contribution of Astrid Lamberts

Title

Hydrodynamics of colliding wind binaries

Topics

"Stellar structure and evolution"

Keywords

hydrodynamical simulations, binaries, WR 104

Abstract

We investigate the hydrodynamics of the interaction of two supersonic winds in binary systems. The collision of the winds creates two shocks separated by a contact discontinuity. The overall structure depends on the momentum flux ratio of the winds. We use the code RAMSES with adaptive mesh refinement to study the shock structure, neglecting orbital motion. We compare the large-scale shape of the interaction region to analytic solutions. High resolution simulations with an isothermal equation of state lead to the development of thin shell instabilities. Their growth in the simulations depends on the numerical resolution, the Mach number and the momentum flux ratio. The dominant instability seems to be the transverse acceleration instability (TAI). We explain why the TAI will be difficult to trigger at a reasonable computational cost in large scale simulations of winds with high momentum flux ratio, as would be desirable e.g. for the study of mixing in the pinwheel nebula WR104.

Talk