干旱区生态环境知识资源中心

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 optimized to recover meteorites and calculate their pre-entry orbits. The 30cm meteoroid entered at 15.44kms(-1), followed a moderately steep trajectory of 51 degrees to the horizon from 81km down to 19km altitude, where the luminous flight ended at a speed of 3.2kms(-1). Deceleration data indicated one large fragment had made it to the ground. The four person search team recovered a 1.15kg meteorite within 130m of the predicted fall line, after 8h of searching, 6days 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 1Ma, 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 (6) resonance. This makes the connection of Dingle Dell to the Flora family (currently thought to be the origin of LL chondrites) unlikely.