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Velocity distribution of high velocity small fragments produced in collisional disruption of simulated small bodies

模拟小天体碰撞破坏产生的高速小碎片的速度分布

基本信息

批准号：
02640305
负责人：
FUJIWARA Akira
金额：
$ 0.83万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02640305/
关键词：
Hypervelocity impact Disruption Velocity distribution Asteroid Solar system 惑星高速衝突

项目摘要

Velocity distribution of the fragments is an especially fundamental quantity among many outcomes of the large scale catastrophic disruptions airong many small bodies during the formation the planets from planetesimals. In this study we made sirall scale high-velocity collsion experiments in the laboratory, and tried to obtain the velocty distribution of the produced fragments systematically. In the experiments, small nylon spheres (7mm in diameter)were accelerated by a two-stage light-gas gun at velocity 2 - 4km/s against spherical basalt and plaster targets. t4ovement of the fragments produced in the impact was recorded by a high-speed framiriq camera. and a strobe system. The velocities of the fragments of size larger than lmm were determined with the aid of an image-analyzer. The velocity of tl) ne fragments in this size range is less than about 100m/s, and proportional to -1/3 - -1/16 th power of the fragment size both for basalt and plaster tcirgets. To extrapolate other experimental results to the larger scale collisions, we made some considerations and experiments. First, dispersion of the orbital elements among asteroid families shows tliat family asteroids have been ejected from their parent asteroid at velocities of about a few hundred m/s. The apparent contradiction between this fact (larger fragments with higher velocity) and our experimental results (smaller fragments with lower velocity) should be attributed to the difference of rising' and falling time of the shock wave ; they become longer for large scale collision compared witti the laboratory scale. As the fragment velocity is closely related with the propagation of the shock wave and destruction' process, ; 4f-also studied on the mechanism of the cratering on curved surfaces. I'n the future, it is necessary to do impact experiments with varying projectile size to establish a scalitiq law for the velocity distribution which can be applicable for the larger scale impact disruption.

在许多小行星形成行星的过程中，碎片的速度分布是许多小天体大范围灾难性破坏的许多结果中一个特别基本的量。在本研究中，我们在实验室进行了SIRALL规模的高速集结实验，并试图系统地获得产生的碎片的速度分布。在实验中，用两级轻气炮以2-4公里/S的速度加速直径为7 mm的尼龙球对准球形玄武岩和石膏靶。T4碰撞中产生的碎片的移动由高速Framiriq相机记录。还有一个闪光灯系统。用图像分析仪测定了大于1 mm的碎片的速度。在这个粒度范围内，tl)Ne碎片的速度小于约100m/S，并与玄武岩和石灰岩的碎片大小的-1/3-1/16次方成正比。为了将其他实验结果外推到更大范围的碰撞中，我们做了一些考虑和实验。首先，轨道元素在小行星家族中的分散表明，小行星家族的小行星以大约几百米/S的速度从母行星上喷出，这一事实与我们的实验结果(较大的碎片速度较高)和我们的实验结果(较小的碎片速度较低)之间的明显矛盾应归因于冲击波的上升和下降时间的不同；与实验室规模相比，大范围碰撞的冲击波上升和下降的时间变长。由于破片速度与冲击波的传播和破坏过程密切相关，4f-还研究了曲面上的凹陷机理。今后有必要对不同尺寸的弹丸进行冲击实验，以建立适用于较大尺度冲击破坏的速度分布的Scalitiq定律。