Wobbling and precessing jets from warped disks in binary systems

TL;DR

This paper presents the first 3D MHD simulations of jets from warped disks in binary systems, revealing jet precession and deviations from symmetry due to binary interactions.

Contribution

It introduces novel 3D MHD simulations of jets from warped disks in binary systems, demonstrating jet precession and asymmetries caused by binary gravitational effects.

Findings

Jets from single stars are stable and symmetric over 600 rotations.

Binary interactions induce jet inclination and spiral structures in disks.

Evidence of jet precession with a 4-degree opening angle in close binary systems.

Abstract

We present results of the first ever three-dimensional (3D) magnetohydrodynamic (MHD) simulations of the accretion-ejection structure. We investigate the 3D evolution of jets launched symmetrically from single stars but also jets from warped disks in binary systems. We have applied various model setups and tested them by simulating a stable and bipolar symmetric 3D structure from a single star-disk-jet system. Our reference simulation maintains a good axial symmetry and also a bipolar symmetry for more than 600 rotations of the inner disk confirming the quality of our model setup. We have then implemented a 3D gravitational potential (Roche potential) due to a companion star and run a variety of simulations with different binary separations and mass ratios. These simulations show typical 3D deviations from axial symmetry, such as jet inclination outside the Roche lobe or spiral arms forming in the accretion disk. In order to find indication for precession effects, we have also run an exemplary parameter setup, essentially governed by a small binary separation of only $\simeq{200}$ inner disk radii. This simulation shows strong indication that we observe the onset of a jet precession caused by the wobbling of the jet launching disk. We estimate the opening angle of the precession cone defined by the lateral motion of the the jet axis of about 4 degree after about 5000 dynamical time steps.