Observational Signatures of Sub-Relativistic Meteors

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 $\gtrsim 1\mathrm{m}\mathrm{m}$ 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}$$wouldbecapableofdetecting$\gtrsim 1 $\mathrm{m}\mathrm{m}$$ sub-relativistic meteors.