The role of Hall diffusion in the magnetically threaded thin accretion discs

TL;DR

This paper investigates how Hall diffusion influences the magnetic interaction between stars and their accretion discs, showing it reduces the total torque and alters the critical fastness parameter.

Contribution

It introduces a new term accounting for Hall diffusion in the torque calculation of star-disc systems, highlighting its impact on the dynamics.

Findings

Hall diffusion decreases the total torque in star-disc systems.

The critical fastness parameter is lowered by Hall diffusion.

Total torque diminishes as Hall diffusion becomes more prominent.

Abstract

We study role of the Hall diffusion in the magnetic star-disc interaction. In a simplified steady state configuration, the total torque is calculated in terms of the fastness parameter and a new term because of the Hall diffusion. We show the total torque reduces as the Hall term becomes more significant. Also, the critical fastness parameter (at which the total torque is zero) reduces because of the Hall diffusion.