Detecting Earth's Temporarily-Captured Natural Satellites - Minimoons

TL;DR

This study evaluates the effectiveness of current and near-future ground-based and space-based facilities in discovering Earth's temporarily captured natural satellites, highlighting the potential and limitations of various detection methods.

Contribution

The paper provides a comprehensive assessment of the detectability of TCOs using optical, infrared, meteor detection, and radar systems, including new simulation results for radar detection probabilities.

Findings

Ground-based optical surveys can find large TCOs over years.

Targeted Subaru telescope surveys can detect 0.5-1.0 m TCOs in about 5 nights.

Radar systems have over 80% chance to detect >10 cm TCOs with sufficient operation time.

Abstract

We present a study on the discoverability of temporarily captured orbiters (TCOs) by present day or near-term anticipated ground-based and space-based facilities. TCOs (Granvik et al. 2012) are potential targets for spacecraft ren- dezvous or human exploration (Chyba et al. 2014) and provide an opportunity to study the population of the smallest asteroids in the solar system. We find that present day ground-based optical surveys such as Pan-STARRS and ATLAS can discover the largest TCOs over years of operation. A targeted survey conducted with the Subaru telescope can discover TCOs in the 0.5 m to 1.0 m diameter size range in about 5 nights of observing. Furthermore, we discuss the application of space-based infrared surveys, such as NEOWISE, and ground-based meteor detection systems such as CAMS, CAMO and ASGARD in discovering TCOs. These systems can detect TCOs but at a uninteresting rate. Finally, we discuss the application of bi-static radar at Arecibo and Green Bank to discover TCOs. Our radar simulations are strongly dependent on the rotation rate distribution of the smallest asteroids but with an optimistic distribution we find that these systems have > 80% chance of detecting a > 10 cm diameter TCO in about 40 h of operation.