A hybrid steady-state magnetohydrodynamic dust-driven stellar wind model for AGB stars

TL;DR

This paper develops a hybrid magnetohydrodynamic and dust-driven wind model for AGB stars, revealing how magnetic fields and dust parameters influence stellar outflows and the formation of critical points and wind morphology.

Contribution

It introduces a combined wind model incorporating both magnetic and dust effects, analyzing their impact on wind structure and dust formation in AGB stars.

Findings

Dust parameter must be less than one for outflow to occur.

Magnetic-cold spots influence dust formation and wind morphology.

Critical points in the wind are affected by dust and magnetic fields.

Abstract

We present calculations for a magnetised hybrid wind model for Asymptotic Giant Branch (AGB) stars. The model incorporates a canonical Weber-Davis (WD) stellar wind with dust grains in the envelope of an AGB star. The resulting hybrid picture preserves traits of both types of winds. It is seen that this combination requires that the dust-parameter ($\Gamma_{d}$) be less than unity in order to achieve an outflow. The emergence of critical points in the wind changes the nature of the dust-driven outflow, simultaneously, the presence of a dust condensation radius changes the morphology of the magnetohydrodynamic (MHD) solutions for the wind. In this context, we additionally investigate the effect of having magnetic-cold spots on the equator of an AGB star and its implications for dust formation; which are seen to be consistent with previous findings.