A Numerical Analysis of Collisions in the Solar System

艾琳·瑞安行星科学研究所96财年：24个月53,917美元。太阳系碰撞的数值分析。影响行星体生长和演化的一个主要过程是超高速撞击。尽管对撞击现象的一些基本原理有了较好的了解，但撞击地点附近的物质碎片如何以及初始条件如何影响这种碎片一直很难量化。此外，碎裂结果与目标大小的依赖关系也没有很好的定义。瑞安博士和他的同事已经开发并测试了一种用于模拟碰撞碎裂的二维拉格朗日流体代码。由于程序中包含了引力效应，因此它在实验室研究范围之外的大规模碰撞事件的模拟中非常有用。在给定一组特定初始条件的情况下，能够描述任何大小的撞击事件的结果的能力适用于许多问题：例如，小行星对行星表面的撞击、小行星带的碰撞演化、小行星家族的形成、行星微小吸积、环状粒子动力学和陨石输送机制。瑞安博士目前研究的目标是通过修改二维码来改进撞击事件的建模，以包括目标孔隙率/内部裂缝的影响。在第二个资助年度，该守则将扩展至3个层面。这个模型的结果将应用于更好地理解太阳系中的碰撞和碰撞，主要是小行星家族的形成问题。====================================================

Eileen Ryan Planetary Science Institute FY 96: $53,917 For 24 months. A Numerical Analysis of Collisions in the Solar System. A major process affecting the growth and evolution of planetary bodies is hypervelocity impact. Although some of the basic principles of impact phenomena are moderately well understood, how material fragments near the impact site and how initial conditions affect that fragmentation have been difficult to quantify. Also, the dependence of fragmentation outcome on target size is not well defined. Dr. Ryan and colleagues have developed and tested a two-dimensional Lagrangian hydrocode for modeling collisional fragmentation. Since gravitational effects are incorporated into the code, it is highly useful in the simulation of large-scale impact events beyond the reach of laboratory studies. The ability to characterize the outcome of an impact event of any size given a particular set of initial conditions is applicable to many problems: asteroid impacts on planetary surfaces, collisional evolution of the asteroid belt, asteroid family formation, planetesimal accretion, ring particle dynamics, and meteorite delivery mechanisms, for example. The goal of Dr. Ryan's present study is to improve the modeling of impact events by modifying the 2-dimensional code to include the effect of target porosity/internal fractures. The code will then be extended to 3 dimensions during the second funding year. The results of this modeling will be applied to better undertand collisions in the Solar System, primarily the problem of the formation of asteroid families. ====================================================