Observational Signatures of Sub-Relativistic Meteors

TL;DR

This paper models the detectability of sub-relativistic meteors larger than 1 mm, showing they produce acoustic shocks and can be observed with optical networks, advancing understanding of high-speed extraterrestrial particles.

Contribution

It introduces a hydrodynamic and radiative model to predict observational signatures of sub-relativistic meteors, highlighting new detection methods.

Findings

Sub-relativistic meteors generate detectable acoustic shocks.

Optical camera networks can observe meteors larger than 1 mm.

A significant fraction of meteor energy causes plasma expansion.

Abstract

It is currently unknown whether solid particles larger than dust from supernova ejecta rain down on Earth at high speeds. We develop a hydrodynamic and radiative model to explore the detectability of $\gtrsim 1 \mathrm{\; mm}$ sub-relativistic meteors. We find that a large fraction of the meteor energy during its passage through the Earth's upper atmosphere powers the adiabatic expansion of a hot plasma cylinder, giving rise to acoustic shocks detectable by infrasound microphones. Additionally, a global network of several hundred all-sky optical cameras with a time resolution of $\lesssim 10^{-4} \mathrm{\;s}$ would be capable of detecting $\gtrsim 1 \mathrm{\; mm}$ sub-relativistic meteors.