The invisible threat: assessing the collisional hazard posed by the undiscovered Venus co-orbital asteroids

TL;DR

This study evaluates the potential collision risk of undiscovered Venus co-orbital asteroids with Earth, analyzing their detectability through models and simulations, and discusses future observational prospects with ground and space-based telescopes.

Contribution

It introduces semi-analytical and numerical models to assess the hazard and observability of Venus co-orbitals, highlighting the importance of future surveys and space missions.

Findings

Venus co-orbitals with e < 0.38 can threaten Earth.

Current observations are limited by observational windows.

Next-generation surveys like Rubin Observatory may detect some co-orbitals.

Abstract

Currently, 20 co-orbital asteroids of Venus are known, with only one with an eccentricity below 0.38. This is most likely caused by observational biases since asteroids with larger eccentricities may approach the Earth and are easier to detect. We aim to assess the possible threat that the yet undetected population of Venus co-orbitals may pose to Earth, and investigate their detectability from Earth and space observatories. We used semi-analytical models of the 1:1 mean-motion resonance with Venus and numerical simulations to monitor close encounters with Earth on several co-orbital cycles. We analyzed observability windows and brightness variations for potential Venus co-orbitals as viewed from ground-based telescopes to assess their future detection feasibility with next-generation survey capabilities. There is a range of orbits with e < 0.38, larger at lower inclinations, for which Venus' co-orbitals can pose a collisional hazard to Earth. Current ground-based observations are constrained by periodic observing windows and solar elongation limitations, though the Rubin Observatory may detect some of these objects during favorable configurations. Space missions based on Venus' orbits may be instrumental in detecting Venus' co-orbitals at low eccentricities.