A Numerical Analysis of Collisions in the Solar System

艾琳·瑞安行星科学研究所：53,917美元，24个月。 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。 虽然人们对撞击现象的一些基本原理有一定的了解，但撞击地点附近的物质如何碎裂以及初始条件如何影响碎裂，一直难以量化。 此外，碎片化结果对目标大小的依赖性也没有很好地定义。 Ryan博士和他的同事们开发并测试了一个用于模拟碰撞碎裂的二维拉格朗日水动力代码。 由于重力效应被纳入代码，它是非常有用的模拟大规模的影响事件超出了实验室研究的范围。 在给定一组特定的初始条件下，描述任何规模的撞击事件的结果的能力适用于许多问题：例如，小行星撞击行星表面，小行星带的碰撞演变，小行星家族的形成，星子吸积，环粒子动力学和陨石输送机制。 Ryan博士目前研究的目标是通过修改二维代码以包括目标孔隙度/内部裂缝的影响来改进撞击事件的建模。 该代码将在第二个供资年度扩展到3个维度。 这一建模的结果将被应用于更好地undertand碰撞在太阳系中，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. ====================================================