Observation of metre-scale impactors by the Desert Fireball Network

TL;DR

This study evaluates the effectiveness of the Desert Fireball Network in detecting and characterizing metre-scale impactors, highlighting data accuracy issues and comparing ground-based observations with orbital sensors over three years.

Contribution

It provides an assessment of fireball network capabilities for metre-scale impactors and discusses limitations of current orbital sensors in impactor characterization.

Findings

Orbital sensors have limited accuracy in velocity measurements.

Fireball networks face dynamic range challenges with large meteoroids.

Ground-based observations are crucial for accurate impactor data.

Abstract

The Earth is impacted by 35-40 metre-scale objects every year. These meteoroids are the low mass end of impactors that can do damage on the ground. Despite this they are very poorly surveyed and characterised, too infrequent for ground based fireball bservation efforts, and too small to be efficiently detected by NEO telescopic surveys whilst still in interplanetary space. We want to evaluate the suitability of different instruments for characterising metre-scale impactors and where they come from. We use data collected over the first 3 years of operation of the continent-scale Desert Fireball Network, and compare results with other published results as well as orbital sensors. We find that although the orbital sensors have the advantage of using the entire planet as collecting area, there are several serious problems with the accuracy of the data, notably the reported velocity vector, which is key to getting an accurate pre-impact orbit and calculating meteorite fall positions. We also outline dynamic range issues that fireball networks face when observing large meteoroid entries.