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Title: Rotation-dependent catastrophic disruption of gravitational aggregates

We carry out a systematic exploration of the effect of pre-impact rotation on the outcomes of low-speed collisions between planetesimals modeled as gravitational aggregates. We use pkdgrav, a cosmology code adapted to collisional problems and recently enhanced with a new soft-sphere collision algorithm that includes more realistic contact forces. A rotating body has lower effective surface gravity than a non-rotating one and therefore might suffer more mass loss as the result of a collision. What is less well understood, however, is whether rotation systematically increases mass loss on average regardless of the impact trajectory. This has important implications for the efficiency of planet formation via planetesimal growth, and also more generally for the determination of the impact energy threshold for catastrophic disruption (leading to the largest remnant retaining 50% of the original mass), as this has generally only been evaluated for non-spinning bodies. We find that for most collision scenarios, rotation lowers the threshold energy for catastrophic dispersal. For head-on collisions, we develop a semi-analytic description of the change in the threshold description as a function of the target's pre-impact rotation rate, and find that these results are consistent with the 'universal law' of catastrophic disruption developed by Leinhardt andmore » Stewart. Using this approach, we introduce re-scaled catastrophic disruption variables that take into account the interacting mass fraction of the target and the projectile in order to translate oblique impacts into equivalent head-on collisions.« less
Authors:
; ;  [1] ;  [2]
  1. Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)
  2. Lagrange Laboratory, University of Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur, C.S. 34229, F-06304 Nice Cedex 4 (France)
Publication Date:
OSTI Identifier:
22365647
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 789; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALGORITHMS; ASTEROIDS; COLLISIONS; COSMOLOGY; EVOLUTION; GRAVITATION; MASS TRANSFER; PLANETS; PROJECTILES; ROTATION; SATELLITES; SPHERES; STELLAR WINDS; THRESHOLD ENERGY; TRAJECTORIES