Ejecta fragmentation in impacts into gypsum and water ice

Abstract

Please cite this article as: Miljković, K., Mason, N.J., Zarnecki, J.C., Ejecta fragmentation in impacts into gypsum and water ice, Icarus (2011Icarus ( ), doi: 10.1016Icarus ( /j.icarus.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Ejecta fragmentation in impacts into AbstractUsing the light gas gun at the Open University's hypervelocity impact facility, a series of impact experiments exploring impacts into water ice and gypsum have been performed. Fragmentation of solid ejecta was recorded using two different methods, analysed and compared with the total ejecta. Preliminary results show that the size distribution of the ejecta fragments from water ice is very similar to those from gypsum. These results also represent a step towards a better understanding of ejecta fragmentation in geological materials, including icy surfaces in the Solar system.

Frictional velocity-weakening in landslides on Earth and on other planetary bodies

“…Theoretical and experimental studies [45][46][47] have shown that similar behaviour can be observed for water ice at low temperatures and for rocky materials, suggesting that flash heating might occur on ice 48 . However, quantitative differences between planetary bodies similar to the variability observed between different rocky materials on Earth is expected.…”

Correlation between speed and size for ejecta from hypervelocity impacts

“…The index α depends on the target material and ranges from 1.5 for loose to 3 for solid targets [ Krivov and Jurewicz , ]. For impacts into pure ice [ Frisch , ; Miljković et al , ] and ice‐silicate mixtures [ Koschny and Grün , ], the value is α = 1.5…1.7, while for impacts into basalt it is α = 2.7 [ Durda and Flynn , ]. Values of α = 1.65…2.37 are consistent with in situ measurements of ejecta from Ganymede [ Krüger et al , ].…”

Dynamic fragmentation of planetary materials: Sub-hypervelocity ejecta measurements and velocity scaling

“…(5)). Single power-law curves are often used for grouped data (Grady, 2009;Miljkovic et al, 2011). For example, the total number of ejecta between 10 mm and 100 mm in size is plotted at the midpoint, 55 mm.…”