# Misaligned accretion disc formation via Kozai-Lidov oscillations

## TL;DR

This study uses simulations to explore how Kozai-Lidov oscillations can lead to the formation of misaligned accretion discs around secondary stars in binary systems, revealing conditions that maximize mass transfer and disc misalignment.

## Contribution

It demonstrates how Kozai-Lidov oscillations influence misaligned disc formation and quantifies mass transfer dependencies on system parameters through SPH simulations.

## Key findings

- Up to 10% of primary disc mass transferred to secondary.
- Secondary discs form with high eccentricity and inclination.
- Circumbinary discs can also form from escaping material.

## Abstract

We investigate the formation and evolution of misaligned accretion discs around the secondary component of a binary through mass transfer driven by Kozai-Lidov oscillations of the circumprimary disc's eccentricity and inclination. We perform SPH simulations to study the amount of mass transferred to the secondary star as a function of both the disc and binary parameters. For the range of parameters we explore, we find that increasing the disc aspect ratio, viscosity parameter and initial inclination as well as decreasing the binary mass ratio leads to larger amount of mass transfer, up to a maximum of about ten per cent of the initial mass of the primary disc. The circumsecondary disc forms with a high eccentricity and a high inclination and is also able to undergo KL oscillations. The circumsecondary disc oscillations have a shorter period than those in the disc around the primary. We find that some of the material that escapes the Roche-lobe of the two components forms a narrow misaligned circumbinary accretion disc. This study has implications for disc evolution in young binary star systems.