Disruption of fragmented parent bodies as the origin of asteroid families
Disruption of fragmented parent bodies as the origin of asteroid families
复制标题
支离破碎的母体的破坏是小行星家族的起源
作者：
P. Michel;W. Benz;D. Richardson
小行星家族是一组共享某些轨道和光谱特性的小天体。目前已确定了 20 多个家族，每个家族都被认为是由一个大型母体碰撞破裂造成的，在这种情况下，重力对碰撞结果的影响超过了岩石的材料强度。家庭成员的大小和速度分布为检验我们对分裂过程的理解提供了重要的约束，但随着时间的推移，轨道的侵蚀和动态扩散可以消除碰撞的原始特征。最近发现的年轻卡琳家族提供了一个独特的机会来研究几乎不受轨道演化影响的碰撞结果。在这里，我们报告了模拟碰撞类别的数值模拟，再现了卡林族的主要特征。碰撞结果对母体内部结构的敏感性使我们能够证明，家庭一定起源于预先破碎的母体的分裂，并且所有大家庭成员都是由较小天体的引力重新积累形成的。我们认为大多数已识别的小行星家族可能都有类似的历史。
Asteroid families are groups of small bodies that share certain orbit and spectral properties. More than 20 families have now been identified, each believed to have resulted from the collisional break-up of a large parent body in a regime where gravity controls the outcome of the collision more than the material strength of the rock. The size and velocity distributions of the family members provide important constraints for testing our understanding of the break-up process, but erosion and dynamical diffusion of the orbits over time can erase the original signature of the collision. The recently identified young Karin family provides a unique opportunity to study a collisional outcome almost unaffected by orbit evolution. Here we report numerical simulations modelling classes of collisions that reproduce the main characteristics of the Karin family. The sensitivity of the outcome of the collision to the internal structure of the parent body allows us to show that the family must have originated from the break-up of a pre-fragmented parent body, and that all large family members formed by the gravitational reaccumulation of smaller bodies. We argue that most of the identified asteroid families are likely to have had a similar history.