Premium
Effect of target properties and impact velocity on ejection dynamics and ejecta deposition
Author(s) -
Luther Robert,
Zhu MengHua,
Collins Gareth,
Wünnemann Kai
Publication year - 2018
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/maps.13143
Subject(s) - ejecta , impact crater , projectile , mechanics , scaling , geology , deposition (geology) , materials science , physics , geometry , mathematics , astrophysics , geomorphology , sediment , astronomy , supernova , metallurgy
Abstract Impact craters are formed by the displacement and ejection of target material. Ejection angles and speeds during the excavation process depend on specific target properties. In order to quantify the influence of the constitutive properties of the target and impact velocity on ejection trajectories, we present the results of a systematic numerical parameter study. We have carried out a suite of numerical simulations of impact scenarios with different coefficients of friction (0.0–1.0), porosities (0–42%), and cohesions (0–150 MP a). Furthermore, simulations with varying pairs of impact velocity (1–20 km s −1 ) and projectile mass yielding craters of approximately equal volume are examined. We record ejection speed, ejection angle, and the mass of ejected material to determine parameters in scaling relationships, and to calculate the thickness of deposited ejecta by assuming analytical parabolic trajectories under Earth gravity. For the resulting deposits, we parameterize the thickness as a function of radial distance by a power law. We find that strength—that is, the coefficient of friction and target cohesion—has the strongest effect on the distribution of ejecta. In contrast, ejecta thickness as a function of distance is very similar for different target porosities and for varying impact velocities larger than ~6 km s −1 . We compare the derived ejecta deposits with observations from natural craters and experiments.