The Dynamics of Objects in Orbits Resembling That of P/Encke

Abstract

The overall orbital evolution of bodies resembling that of P/Encke is studied by numerical integration. Dynamical paths are found that connect orbits of this type to their possible sources, i.e., the asteroidal main belt and the Jupiter family of comets. Possible end-states for these orbits include ejection from the region of the inner planets, due to close encounters with Jupiter, and collision with the Sun. We find a purely gravitational dynamical path (i.e., one not involving nongravitational forces) connecting the orbit of P/Encke to the orbits of the rest of the Jupiter family of comets on a timescale of several times 105 years, somewhat longer than typical cometary physical lifetimes. The hypothesis of a genetic relationship among some or all of the bodies currently in Encke-like orbits is not supported by our results. The existence of dynamical channels linking these orbits to asteroidal and cometary sources explains why both types of objects are present in the Taurid complex and points to the presence of both high-density and low-density material in the related meteoroid population.