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Abstract: The Centaurs are a transient population of small bodies in the outer solarsystem whose orbits are strongly chaotic. These objects typically suffersignificant changes of orbital parameters on timescales of a few thousandyears, and their orbital evolution exhibits two types of behaviors describedqualitatively as random-walk and resonance-sticking. We have analyzed thechaotic behavior of the known Centaurs. Our analysis has revealed that the twotypes of chaotic evolution are quantitatively distinguishable: 1 the randomwalk-type behavior is well described by so-called generalized diffusion inwhich the rms deviation of the semimajor axis grows with time t as ~t^H, withHurst exponent H in the range 0.22-0.95, however 2 orbital evolutiondominated by intermittent resonance sticking, with sudden jumps from one meanmotion resonance to another, has poorly defined H. We further find that thesetwo types of behavior are correlated with Centaur dynamical lifetime: mostCentaurs whose dynamical lifetime is less than ~22 Myr exhibit generalizeddiffusion, whereas most Centaurs of longer dynamical lifetimes exhibitintermittent resonance sticking. We also find that Centaurs in the diffusingclass are likely to evolve into Jupiter-family comets during their dynamicallifetimes, while those in the resonance-hopping class do not.

Author: B.L. Bailey, Renu Malhotra


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