Magnetic Imprisonment of Dusty Pinballs by a Supernova Remnant

TL;DR

This study models how dust grains containing $^{60}$Fe from a nearby supernova are transported and affected within the supernova remnant, highlighting magnetic fields' role in trapping or reflecting dust, which impacts in situ measurements.

Contribution

It introduces a combined hydrodynamic and magnetic field model to analyze dust grain trajectories and survival within supernova remnants, emphasizing magnetic effects on dust transport.

Findings

Magnetic fields limit dust grain passage in SNRs.

Rayleigh-Taylor instabilities influence dust survival.

Magnetic trapping affects $^{60}$Fe deposit locations.

Abstract

Motivated by recent measurements of deposits of $^{60}$Fe on the ocean floor and the lunar surface, we model the transport of dust grains containing $^{60}$Fe from a near-Earth (i.e., within 100 pc) supernova (SN). We inject dust grains into the environment of an SN remnant (SNR) and trace their trajectories by applying a 1D hydrodynamic description assuming spherical symmetry to describe the plasma dynamics, and include a rudimentary, 3D magnetic field description to examine its influence on charged dust grains. We assume the interstellar medium (ISM) magnetic fields are turbulent, and are amplified by the SNR shock, while the SN wind and ejecta fields are negligible. We examine the various influences on the dust grains within the SNR to determine when/if the dust decouples from the plasma, how much it is sputtered, and where within the SNR the dust grains are located. We find that Rayleigh-Taylor instabilities are important for dust survival, as they influence the location of the SN's reverse shock. We find that the presence of a magnetic field within the shocked ISM material limits the passage of SN dust grains, with the field either reflecting or trapping the grains within the heart of the SNR. These results have important implications for {\it in situ} $^{60}$Fe measurements, and for dust evolution in SNRs generally.