Arpu Kuilpu: An H5 from the Outer Main Belt

TL;DR

This paper reports the detection, trajectory analysis, and recovery of the Arpu Kuilpu meteorite, the smallest meteoroid to survive atmospheric entry and be recovered as an H5 ordinary chondrite, originating from the outer main belt.

Contribution

It presents a detailed case study of a small meteoroid from detection to recovery, demonstrating the Desert Fireball Network's capability to recover small meteorites from outer main belt origins.

Findings

Recovered a 42 g meteorite confirming a fresh fall.

Trajectory analysis indicates an origin from the outer main belt.

First small meteoroid (~2 kg) recovered as a meteorite from this region.

Abstract

On 1 June 2019, just before 7:30 PM local time, the Desert Fireball Network detected a -9.3 magnitude fireball over South Australia near the Western Australia border. The event was observed by six fireball observatories, and lasted for five seconds. One station was nearly directly underneath the trajectory, greatly constraining the trajectory solution. This trajectory's backward numerical integrations indicate that the object originated from the outer main belt with a semi-major axis of 2.75 au. A light curve was also extracted and showed that the body experienced very little fragmentation during its atmospheric passage. A search campaign was conducted with several Desert Fireball Network team members and other volunteers. One 42 g fragment was recovered within the predicted fall area based on the dark flight model. Based on measurements of short-lived radionuclides, the fragment was confirmed to be a fresh fall. The meteorite, Arpu Kuilpu, has been classified as an H5 ordinary chondrite. This marks the fifth fall recovered in Australia by the Desert Fireball Network, and the smallest meteoroid ($\simeq 2$ kg) to ever survive entry and be recovered as a meteorite.