Close encounters of the primordial kind: a new observable for primordial black holes as dark matter

TL;DR

This paper proposes that asteroid-mass primordial black holes as dark matter could be detected through their gravitational perturbations on Solar System objects, offering a new observational method.

Contribution

It introduces the idea that close encounters of primordial black holes with the Solar System can serve as a novel observable for dark matter detection.

Findings

Close encounters occur roughly once per decade.

Perturbations could be detectable with current high-precision data.

Existing and upcoming data can plausibly constrain PBH abundance.

Abstract

Primordial black holes (PBHs) remain a viable dark matter candidate in the asteroid-mass range. We point out that in this scenario, the PBH abundance would be large enough for at least one object to cross through the inner Solar System per decade. Since Solar System ephemerides are modeled and measured to extremely high precision, such close encounters could produce detectable perturbations to orbital trajectories with characteristic features. We evaluate this possibility with a suite of simple Solar System simulations, and we argue that the abundance of asteroid-mass PBHs can plausibly be probed by existing and near-future data.