![]() ![]() Wakita, and the LOC of iSALE workshop 2019 at CfCA. I am grateful for the iSALE users group in Japan, including K. Numerical computations were carried out on PC cluster at Center for Computational Astrophysics (CfCA), National Astronomical Observatory of Japan. In this poster, the detailed analysis of the crater morphologies will be described.Īcknowledgments: I appreciate the developers of iSALE, including G. With the increase of the aspect ratio of the projectile, the depth of the crater increased, while its diameter was almost unchanged. After the calculations, the depth and diameter of the crater were measured. A gravity of 9.8 m/s 2 was included in the calculation. The aspect ratio was varied from 0.36 (disk) to 8.0 (rod), while the volume was almost constant. The Tillotson EOS for iron and quartz were used. A cylinder with an aspect ratio (height/width) and a uniform sand layer was used as the projectile and the target. In this work, I use the iSALE shock physics code (Amsden et al., 1980 Collins et al., 2004 Wünnemann et al., 2006). In this study, I report a tentative numerical study on the effect of the aspect ratio of a cylindrical projectile on the crater morphology. However, it is not obvious whether irregular-shaped debris produces typical bowl-shaped craters, although the effect of SCI-like hollow-shaped projectile has been investigated numerically (Kurosawa et al., 2015). These concentric features, including sub-crater candidates, were also observed on the surface of Ryugu. Besides the main copper liner, the SCI produces irregular-shaped forward debris composed of copper or SUS that form concentric features on the target surface. However, these data are in conflict with trajectories inferred from the analysis of infrasound signals.The small carry-on impactor (SCI) onboard the Hayabusa2 spacecraft successfully detonated on April 5, 2019, and created an artificial crater on the surface of asteroid Ryugu. Aerodynamic and crater modeling are consistent with field data and our microscopic inspection. This scenario results in a strong meteoroid deceleration, a deflection of the trajectory to a steeper impact angle (40–60 °), and an impact velocity of 350–600 ms−1, which is insufficient to produce a shock wave and significant shock effects in target minerals. By modeling the atmospheric traverse we demonstrate that low cosmic velocities (12–14 kms−1) and shallow entry angles (<20 °) are prerequisites to keep aerodynamic stresses low (<10 MPa) and thus to prevent fragmentation of stony meteoroids with standard strength properties. Depending on the strength properties of the target, the impact energies range between approximately 100–1000 MJ (0.024–0.24 t TNT). To constrain the possible range of impact parameters we carried out numerical models of crater formation with the iSALE hydrocode in two and three dimensions. We present results of a detailed geologic survey of the crater and its ejecta. The Carancas cratering event, however, demonstrates that meter-sized stony meteoroids indeed can survive the atmospheric passage under specific circumstances. The small fragments that result from a breakup rain down at terminal velocity and are not capable of producing impact craters. Fragmentation occurs if the strength of the meteoroid is less than the aerodynamic stresses that occur in flight. The impact violated the hitherto existing view that stony meteorites below a size of 100 m undergo major disruption and deceleration during their passage through the atmosphere and are not capable of producing craters. ![]() It is the smallest, youngest, and one of two eye-witnessed impact crater events on Earth. ![]() An H4–5 chondrite struck the Earth south of Lake Titicaca in Peru on September 15, 2007, and formed a crater 14.2 m across. The primary purpose of iSALEPlot is to visualise iSALE data using 2D contour (colormap) plots or 1D linegraph profiles. iSALEPlot is controlled by options in an input file and command line arguments. Abstract- The recent Carancas meteorite impact event caused a worldwide sensation. iSALEPlot iSALEPlot is a plotting program for visualization and post-processing of data produced by iSALE. ![]()
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