Numerical modeling of asteroid survivability and possible scenarios for the Morokweng crater-forming impact
Article first published online: 28 MAR 2013
© The Meteoritical Society, 2013.
Meteoritics & Planetary Science
Volume 48, Issue 5, pages 744–757, May 2013
How to Cite
Potter, R. W. K. and Collins, G. S. (2013), Numerical modeling of asteroid survivability and possible scenarios for the Morokweng crater-forming impact. Meteoritics & Planetary Science, 48: 744–757. doi: 10.1111/maps.12098
- Issue published online: 13 MAY 2013
- Article first published online: 28 MAR 2013
- Manuscript Accepted: 5 FEB 2013
- Manuscript Received: 28 AUG 2012
- NASA Lunar Science Institute Cooperative Agreement. Grant Numbers: NE/E013589/1, ST/G002452/1
- STFC. Grant Numbers: NE/E013589/1, ST/G002452/1, NNX08AC28A
The fate of the impactor is an important aspect of the impact-cratering process. Defining impactor material as surviving if it remains solid (i.e., does not melt or vaporize) during crater formation, previous numerical modeling and experiments have shown that survivability decreases with increasing impact velocity, impact angle (with respect to the horizontal), and target density. Here, we show that in addition to these, impactor survivability depends on the porosity and shape of the impactor. Increasing impactor porosity decreases impactor survivability, while prolate-shaped (polar axis > equatorial axis) impactors survive impact more so than spherical and oblate-shaped (polar axis < equatorial axis) impactors. These results are used to produce a relatively simple equation, which can be used to estimate the impactor fraction shocked to a given pressure as a function of these parameters. By applying our findings to the Morokweng crater-forming impact, we suggest impact scenarios that explain the high meteoritic content and presence of unmolten fossil meteorites within the Morokweng crater. In addition to previous suggestions of a low-velocity and/or high-angled impact, this work suggests that an elongated and/or low porosity impactor may also help explain the anomalously high survivability of the Morokweng impactor.