论文标题
实验室冲击飞溅实验以模拟小行星表面
Laboratory Impact Splash Experiments to Simulate Asteroid Surfaces
论文作者
论文摘要
由小行星的低重力结合的颗粒材料受到缓慢的速度影响动员的颗粒材料。这些撞击产生的飞溅可能在雕刻小行星表面中起重要作用。在实验室实验中，我们表征了球形150 $ \ rmμm$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $的玄武岩晶粒，影响颗粒床0.8 m/s。我们发现，这种影响通常会导致从颗粒床中弹出的少于10个颗粒，典型的喷射轨迹上升到表面上方不到一个颗粒直径不到一个。也就是说，观察到的影响是高度耗散的，只有一小部分影响能量被赋予喷射。尽管影响器本身仍然反弹，但通常会大大减少其影响速度的20％。缩放到小行星，撞击器和由砂粒的撞击产生的撞击器和喷射，无法分布在小行星表面上，但将保持靠近撞击部位。因此，与对裸露的岩石表面更具弹性影响相比，这些高度无弹性对软颗粒床有效地捕获了晶粒，这证实了Shinbrot（2017）的建议。这也与观察到的小行星特征同意，因为这种拓扑弹性偏置表明谷物的重新分布会导致大小隔离。
Granular material that is bound by the low gravity of a small asteroid is mobilized by slow velocity impacts. These splashes generated by impacts might play an important role in sculpting the asteroid's surface. In laboratory experiments we characterize the ejecta generated by spherical 150 $\rm μm$ diameter basalt grains impacting a granular bed at 0.8 m/s. We find that such an impact typically leads to less than 10 particles being ejected from the granular bed, with typical ejecta trajectories rising to less than one particle diameter above the surface. That is, the observed impacts are highly dissipative and only a small fraction of the impact energy is imparted onto the ejecta. While the impactor itself still rebounds, it typically slows down significantly to an average of about 20 % of its impact velocity. Scaled to asteroids, impactor and ejecta generated from impacts of sand sized grains are not able to spread over the asteroid's surface but will stay close to the impact site. Therefore these highly inelastic impacts into soft granular beds efficiently trap grains, in contrast to more elastic impacts on bare, rocky surfaces confirming suggestions by Shinbrot (2017). This is also in agreement to observed features on asteroids as this topological elasticity bias suggests that redistribution of grains leads to a size segregation.
