Enhancement of Impact Heating in Pressure‐Strengthened Rocks in Oblique Impacts

Abstract

Shock-induced metamorphism in meteorites informs us about the collisional environment and history of our solar system. Recently, the importance of material strength in impact heating was reported from head-on impact simulations. Here, we perform three-dimensional oblique impact simulations and confirm the additional heating due to material strength for oblique impacts. Despite a large difference in the peak pressure at the impact point at a given impact velocity, we find that the heated mass for an oblique impact is nearly the same as that for a head-on impact. Thus, our results differ from the previous finding that the heated mass decreases as the impact becomes more oblique and show that the additional shear heating is more effective for oblique impacts than for head-on impacts. This also indicates that material ejected during oblique impact tends to experience lower shock pressures but higher temperatures.

Effect of Impact Velocity and Angle on Deformational Heating and Postimpact Temperature

“…Comparing impacts with and without material strength (Figure 2), we can confirm that material strength enhances the temperature increase. This is consistent with previous work (Kurosawa & Genda, 2018; Wakita et al., 2019). As confirmed in Kurosawa and Genda (2018), more kinetic energy is converted into internal energy in the target with material strength.…”

“…Also, we have confirmed that the cumulative heated mass is similar at 2.5–10 t s and does not change significantly after 5 t s (see Figure S5 in Wakita et al. [2019]).…”

“…The mass heated by oblique impacts is a key to the understanding of the history of asteroids and meteorites. While Kurosawa and Genda (2018) clarified the importance of the material strength of the target in the vertical impact, the following work confirmed this in the oblique impacts at a given impact velocity and angles (Wakita et al., 2019). We advanced their work by examining the dependence of the impact velocities and angles.…”

The Role of Post‐Shock Heating by Plastic Deformation During Impact Devolatilization of Calcite (CaCO3)

“…Schultz (1996) used oblique impact experiments to show that shear heating in oblique impacts enhances the total vapor production. Wakita et al (2019) has also shown numerically with the three-dimensional version of iSALE that oblique impacts lead to more efficient post-shock heating due to plastic deformation than vertical impacts. However, the enhancement of post-shock heating by oblique impacts should be tested in future experimental studies.…”

“…Wakita et al. (2019) has also shown numerically with the three‐dimensional version of iSALE that oblique impacts lead to more efficient post‐shock heating due to plastic deformation than vertical impacts. However, the enhancement of post‐shock heating by oblique impacts should be tested in future experimental studies.…”