The impact and recovery of asteroid 2018 LA
Abstract
The June 2, 2018, impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. 23 meteorites were recovered. A consortium study of eight of these classifies Motopi Pan as a HED polymict breccia derived from howardite, cumulate and basaltic eucrite, and diogenite lithologies. Before impact, 2018 LA was a solid rock of about 156 cm diameter with high bulk density about 2.85 g/cm3, a relatively low albedo pV about 0.25, no significant opposition effect on the asteroid brightness, and an impact kinetic energy of about 0.2 kt. The orbit of 2018 LA is consistent with an origin at Vesta (or its Vestoids) and delivery into an Earth-impacting orbit via the nu_6 resonance. The impact that ejected 2018 LA in an orbit towards Earth occurred 22.8 +/- 3.8 Ma ago. Zircons record a concordant U-Pb age of 4563 +/- 11 Ma and a consistent 207Pb/206Pb age of 4563 +/- 6 Ma. A much younger Pb-Pb phosphate resetting age of 4234 +/- 41 Ma was found. From this impact chronology, we discuss what is the possible source crater of Motopi Pan and the age of Vesta's Veneneia impact basin.
Cite
@article{arxiv.2105.05997,
title = {The impact and recovery of asteroid 2018 LA},
author = {Peter Jenniskens and Mohutsiwa Gabadirwe and Qing-Zhu Yin and Alexander Proyer and Oliver Moses and Tomas Kohout and Fulvio Franchi and Roger L. Gibson and Richard Kowalski and Eric J. Christensen and Alex R. Gibbs and Aren Heinze and Larry Denneau and Davide Farnocchia and Paul W. Chodas and William Gray and Marco Micheli and Nick Moskovitz and Christopher A. Onken and Christian Wolf and Hadrien A. R. Devillepoix and Quanzhi Ye and Darrel K. Robertson and Peter Brown and Esko Lyytinen and Jarmo Moilanen and Jim Albers and Tim Cooper and Jelle Assink and Läslo Evers and Panu Lahtinen and Lesedi Seitshiro and Matthias Laubenstein and Nggie Wantlo and Phemo Moleje and Joseph Maritinkole and Heikki Suhonen and Michael E. Zolensky and Lewis Ashwal and Takahiro Hiroi and Derek W. Sears and Alexander Sehlke and Alessandro Maturilli and Matthew E. Sanborn and Magdalena H. Huyskens and Supratim Dey and Karen Ziegler and Henner Busemann and My E. I. Riebe and Matthias M. M. Meier and Kees C. Welten and Marc W. Caffee and Qin Zhou and Qiu-Li Li and Xian-Hua Li and Yu Liu and Guo-Qiang Tang and Hannah L. McLain and Jason P. Dworkin and Daniel P. Glavin and Philippe Schmitt-Kopplin and Hassan Sabbah and Christine Joblin and Mikael Granvik and Babutsi Mosarwa and Koketso Botepe},
journal= {arXiv preprint arXiv:2105.05997},
year = {2021}
}
Comments
Meteoritics & Planetary Science (2021)