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Oblique impact: A process for providing meteorite samples of other planetsCratering flow calculations for a series of oblique to normal impacts of silicate projectiles onto a silicate halfspace were carried out to determine whether the gas produced upon shock vaporizing both projectile and planetary material could entrain and accelerate surface rocks and thus provide a mechanism for propelling SNC meteorites from the Martian surface. The difficult constraints that the impact origin hypothesis for SNC meteorites has to satisfy are that these meteorites are lightly to moderately shocked and yet were accelerated to speeds in excess of the Martian escape velocity. Two dimensional finite difference calculations demonstrate that at highly probable impact velocities, vapor plume jets are produced at oblique impact angles of 25 deg to 60 deg and have speeds as great as 20 km/sec. These plumes flow nearly parallel to the planetary surface. It is shown that upon impact of projectiles having radii of 0.1 to 1 km, the resulting vapor jets have densities of 0.1 to 1 g/cu.cm. These jets can entrain Martian surface rocks and accelerate them to velocities 5 km/sec. It is suggested that this mechanism launches SNC meteorites to Earth.
Document ID
19860012008
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Okeefe, J. D. (California Inst. of Tech. Pasadena, CA, United States)
Ahrens, T. J. (California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 5, 2013
Publication Date
March 10, 1986
Subject Category
Astrophysics
Report/Patent Number
NASA-CR-176616
NAS 1.26:176616
Accession Number
86N21479
Funding Number(s)
CONTRACT_GRANT: NSG-7129
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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