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P. S. Lykawka, T. Mukai (Kobe University)
Current observations of scattered transneptunian objects (TNOs) have been supporting the standard picture of solar system formation: it is believed that these objects were scattered to highly excited and large orbits in the transneptunian region (semimajor axis a>50AU). Therefore, their dynamical evolution can reveal important clues for planetary sciences. We investigate the structure of the scattered region through computer simulations totalizing more than 20000 massless bodies under the effect of the four giant planets over 4-5Gyr. The evolutionary paths were followed in phase space and by orbital 2D and 3D animations as well. We found that: (1) A few percent (1-3%) of the objects survived in the scattered region with direct influence of several neptunian mean motion resonances. This indicates that resonance sticking is an extremely common phenomenon acting as the main mechanism enhancing scattered objects longevity; (2) In the same region, the so-called extended scattered TNOs (perihelion distance q>40AU) are able to form via resonance sticking with two particular conditions: more than about 80% of the object’s dynamical lifetime spent inside mean motion resonance(s) and trapping in k+1 or (k+2)/2 type resonances (e.g., external mean motion resonances described as (j+k)/j with j=1 and j=2 respectively). This hypothetical mechanism predicts that about 5-10% of current scattered TNOs with a<250AU would possess q=40-60AU; (3) The formation of extended scattered TNOs is apparently independent of initial orbital parameters. Besides, planetary migration is also not required; (4) Considering hot initial orbital conditions, it is likely that the classical region (~42-48AU) has been providing members to the scattered region, so that scattered TNOs would consist of primordial scattered bodies mixed with classical ones.
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The author(s) of this abstract have provided an email address for comments about the abstract: patryk@harbor.scitec.kobe-u.ac.jp
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.