Institute of Astronomy

3D AMR Hydrodynamic Simulations of Common Envelope Interactions between Red Giants and Low-mass Companions

SpeakerTalk DateTalk Series
Jan Staff26 July 2016Binary Stars Talks

Abstract

We present results of 3 dimensional adaptive mesh refined grid-based hydrodynamic simulations of an RGB star in a common envelope with a low-mass main sequence companion or a planet. All low mass white dwarfs and short period white dwarf binaries must have undergone at least one common envelope interaction phase. White dwarf binaries may even lead to type Ia supernovae.  Many low mass white dwarfs and white dwarf binary systems are observed, and in order to understand how these systems formed it is therefore necessary to understand the common envelope interaction. Despite this, we find, as in many other simulations of this kind, that not much mass is being unbound in the process, and unless  additional physics is relevant for the interaction, the interaction will therefore lead to a merger. We calculate the drag force acting on the  companion as it spirals in through the envelope, and compare this force with analytic expressions for the force, and find reasonable agreements.

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