Moving-Mesh Simulations of Mini-Common Envelope Ejection in Classical Novae

TL;DR

This study uses 3D moving-mesh hydrodynamic simulations to analyze mass ejection in cataclysmic variables, revealing isotropic ejection post-${\rm L}_1$ crossing and increased angular momentum transfer.

Contribution

First 3D moving-mesh simulation showing the isotropic nature of mass ejection and angular momentum transfer in cataclysmic variables.

Findings

Ejecta are roughly isotropic after crossing ${\rm L}_1$.

${\rm L}_2$ point is not significant in mass ejection.

Ejected material has higher specific angular momentum.

Abstract

Although well studied, our understanding of the mass ejection mechanisms of cataclysmic variables remains incomplete. Recent work suggests that binary interaction plays an important role in driving and shaping this mass ejection and may affect the long-term evolution of the system. In this paper, we perform a three-dimensional moving-mesh hydrodynamic simulation of a cataclysmic variable system to study the effect of binary interaction on mass ejection. We find that once the flow crosses the ${\rm L}_1$ Lagrange point, the material is ejected roughly isotropically. This can be seen in a roughly spherical distribution of the ejecta at large radii. We also show that the ${\rm L}_2$ Lagrange point is not important in the ejection of mass, contrary to the assumption in some previous work in this area. Finally, we find that the specific angular momentum of the ejected material is larger than its initial specific angular momentum. This enhanced angular momentum ejection likely affects the long-term evolution of the binary system.