Fragmentation Model Dependence of Collision Cascades
Fragmentation Model Dependence of Collision Cascades
复制标题
碰撞级联的碎片模型依赖性
DOI：
10.1016/j.icarus.2009.10.004
复制
发表时间：
2010
期刊：
影响因子：
3.2
通讯作者：
Hidekazu Tanaka
中科院分区：
文献类型：
--
作者：
Hiroshi Kobayashi;Hidekazu Tanaka
在研究小行星带、埃奇沃斯-柯伊伯带、碎片盘和行星形成过程中，通过连续的碰撞破坏（即碰撞级联）导致天体的质量耗损是最重要的过程之一。碰撞崩裂分为两种类型，即灾难性崩裂和陨石坑崩裂。虽然一些碰撞级联的研究忽略了陨石坑的影响，但尚不清楚哪种类型的破坏对碰撞级联起主导作用。在本研究中，我们构建了一个简单的结果模型，描述了灾难性破坏和陨石坑，其中一些参数表征了总喷出物质量，最大碎片的质量和碎片尺寸分布的幂律指数。使用这个简单的带参数的结果模型，我们研究了在忽略高碰撞速度导致的碰撞体合并的情况下，碰撞级联中质量耗尽时间的模型依赖性。我们发现，在大范围的模型参数范围内，碰撞级联中的弹坑碰撞比具有灾难性破坏的碰撞更有效。碰撞级联的质量消耗时间主要受喷出物总质量的影响，对实际参数区域内最大碎片的质量和碎片的幂律指数几乎不敏感。总的抛射质量通常由撞击能量除以目标质量（即q值）与灾难性破坏的阈值QD★之比决定，在我们的简单模型中也是如此。我们推导出了一个质量耗尽时间，它是由碰撞级联高质量端的QD★决定的。用我们的模型推导出的质量耗尽时间适用于碎片盘和行星的形成。
Mass depletion of bodies through successive collisional disruptions (i.e., collision cascade) is one of the most important processes in the studies of the asteroids belt, the Edgeworth-Kuiper belt, debris disks, and planetary formation. The collisional disruption is divided into two types, i.e., catastrophic disruption and cratering. Although some studies of the collision cascades neglected the effect of cratering, it is unclear which type of disruption makes a dominant contribution to the collision cascades. In the present study, we construct a simple outcome model describing both catastrophic disruption and cratering, which has some parameters characterizing the total ejecta mass, the mass of the largest fragment, and the power-law exponent of the size distribution of fragments. Using this simple outcome model with parameters, we examine the model dependence of the mass depletion time in collision cascades for neglect of coalescence of colliding bodies due to high collisional velocities. We find the cratering collisions are much more effective in collision cascades than collisions with catastrophic disruption in a wide region of the model parameters. It is also found that the mass depletion time in collision cascades is mainly governed by the total ejecta mass and almost insensitive to the mass of the largest fragment and the power-law exponent of fragments for a realistic parameter region. The total ejecta mass is usually determined by the ratio of the impact energy divided by the target mass (i.e. Q-value) to its threshold value QD★for catastrophic disruption, as well as in our simple model. We derive a mass depletion time in collision cascades, which is determined by QD★of the high-mass end of collision cascades. The mass depletion time derived with our model would be applicable to debris disks and planetary formation.