Detectability of Thermal Emission from Sub-Relativistic Objects

TL;DR

This paper calculates the thermal emission of fast-moving, sub-relativistic objects in the Solar system, showing that upcoming telescopes like JWST can detect such objects and constrain their abundance.

Contribution

It introduces a method to estimate thermal emission from sub-relativistic objects and assesses their detectability with future telescopes.

Findings

Objects larger than 100 m and moving faster than 0.1c are detectable by JWST up to 100 au.

Future surveys can constrain the abundance of fast interstellar objects or spacecraft.

Thermal emission depends on collisional and radiative heating mechanisms.

Abstract

We calculate the surface temperature and the resulting brightness of sub-relativistic objects moving through the Solar system due to collisional heating by gas and radiative heating by solar radiation. The thermal emission from objects of size $\gtrsim 100$ m and speed of $\gtrsim 0.1c$, can be detected by the upcoming {\it James Webb Space Telescope} out to a distance of $\sim 100$ au. Future surveys could therefore set interesting limits on the abundance of fast-moving interstellar objects or spacecraft.