[PPS07-25] Likelihood for rubble-pile near-Earth asteroids to be 1st or Nth generation: focus on Bennu and Ryugu
Keywords:Near-Earth Asteroids, Rubble Pile Asteroids
We created a model that tracked the survival of asteroid disruption remnants to understand the likelihood that they are direct rubble-pile products of a large asteroid family (1st generation) or the product of a slightly larger rubble pile that itself is the product of a larger asteroid family (2nd generation...up to Nth generation). The competition is between the very large numbers of the 1st generation km-sized family members racing against time to reach an escape route before being destroyed in a collision—versus 5- to 10-km rubble piles, moving much more slowly but more resistant to immediate destruction, being broken up eventually and having some of their remnants escape. We find that for scenarios in the inner Main Belt, the total number of escaping bodies is dominated by 1st generation rubble piles. For older families, those whose age is two or three times the collisional lifetime of the NEA of interest, the bodies reaching escape routes can be equal contributions of 1st and Nth generation rubble piles. Thus, the answer to whether a specific NEA is more likely a 1st or Nth generation rubble pile depends on knowledge of its parent family and that family’s age.