# Effects of Barnett magnetic dipole-dipole interaction on grain growth and destruction

## TL;DR

This paper investigates how Barnett magnetic dipole-dipole interactions influence grain collisions and growth in astrophysical environments, highlighting the role of magnetic properties and radiation fields in dust evolution.

## Contribution

It introduces the novel effect of Barnett magnetic dipole-dipole interaction on grain collision rates, emphasizing its significance in astrophysical dust processes.

## Key findings

- Collision rates are significantly enhanced for grains with iron inclusions.
- Barnett magnetic interactions depend on grain rotation and magnetic properties.
- Implications for grain growth and destruction in various astrophysical environments.

## Abstract

Rapidly spinning magnetic grains can acquire large magnetic dipole moments due to the Barnett effect. Here we study the new effect of Barnett magnetic dipole-dipole interaction on grain-grain collisions and grain growth, assuming grains spun up by radiative torques. We find that the collision rate between grains having embedded iron inclusions can be significantly enhanced due to Barnett magnetic dipole-dipole interaction when grains rotate suprathermally by radiative torques. We discuss the implications of enhanced collision rate for grain growth and destruction in the circumstellar envelope of evolved stars, photodissociation regions, and protostellar environments. Our results first reveal the importance of the dust magnetic properties and the local radiation field on grain growth and destruction.