The Dingle Dell meteorite: a Halloween treat from the Main Belt

Abstract

We describe the fall of the Dingle Dell (L/LL 5) meteorite near Morawa in Western Australia on October 31, 2016. The fireball was observed by six observatories of the Desert Fireball Network (DFN), a continental scale facility optimised to recover meteorites and calculate their pre-entry orbits. The $30\,\mbox{cm}$ meteoroid entered at 15.44 $\mbox{km s}^{-1}$, followed a moderately steep trajectory of $51^{\circ}$ to the horizon from 81 km down to 19 km altitude, where the luminous flight ended at a speed of 3.2 $\mbox{km s}^{-1}$. Deceleration data indicated one large fragment had made it to the ground. The four person search team recovered a 1.15 kg meteorite within 130 m of the predicted fall line, after 8 hours of searching, 6 days after the fall. Dingle Dell is the fourth meteorite recovered by the DFN in Australia, but the first before any rain had contaminated the sample. By numerical integration over 1 Ma, we show that Dingle Dell was most likely ejected from the main belt by the 3:1 mean-motion resonance with Jupiter, with only a marginal chance that it came from the $nu_6$ resonance. This makes the connection of Dingle Dell to the Flora family (currently thought to be the origin of LL chondrites) unlikely.