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TY - JOUR AU - Michel, Patrick AU - Benz, Willy AU - Richardson, Derek C. PY - 2003 DA - 2003/02/01 TI - Disruption of fragmented parent bodies as the origin of asteroid families JO - Nature SP - 608 EP - 611 VL - 421 IS - 6923 AB - Asteroid families are groups of small bodies that share certain orbit1 and spectral properties2. More than 20 families have now been identified, each believed to have resulted from the collisional break-up of a large parent body3 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 collision4,5. The recently identified young Karin family6 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. SN - 1476-4687 UR - https://doi.org/10.1038/nature01364 DO - 10.1038/nature01364 ID - Michel2003 ER -