Capture of primordial black holes in extrasolar systems

TL;DR

This paper explores the potential for extrasolar systems to capture primordial black holes, highlighting that such events are rare unless PBHs make up all dark matter in a specific mass range, with possible observable signatures.

Contribution

It introduces the concept of primordial black hole capture in extrasolar systems and estimates the capture rates considering various mechanisms, identifying conditions for detectability.

Findings

Capture rate is negligible unless PBHs constitute all dark matter in a narrow mass range.

Luminous evaporating PBHs could be detectable by exoplanet searches under certain conditions.

Capture mechanisms vary, but overall likelihood remains low outside specific scenarios.

Abstract

The vast datasets associated with extrasolar systems promise to offer sensitive probes of new physics in the near future. We consider the possibility that such systems may capture primordial black holes (PBHs) or other exotic compact objects, giving rise to unique observational signatures. We estimate the rate of captures by extrasolar systems, accounting for several distinct mechanisms. We find that the capture rate is negligible unless PBHs account for the entirety of dark matter in a narrow mass range just above the threshold of existing constraints from evaporation. In this scenario, luminous evaporating PBHs may be detectable by exoplanet searches.