The Dynamics of Dust Grains in the Outer Solar System

Abstract

We study the dynamics of large dust grains >1 micron with orbits outside of the heliosphere (beyond 250 AU). Motion of the Solar System through the interstellar medium (ISM) at a velocity of 26 km/s subjects these particles to gas and Coulomb drag (grains are expected to be photoelectrically charged) as well as the Lorentz force and the electric force caused by the induction electric field. We show that to zeroth order the combined effect of these forces can be well described in the framework of the classical Stark problem: particle motion in a Keplerian potential subject to an additional constant force. Based on this analogy, we elucidate the circumstances in which the motion becomes unbound, and show that under local ISM conditions dust grains smaller than ~100 microns originating in the Oort Cloud (e.g. in collisions of comets) beyond 10000 AU are ejected from the Solar System under the action of the electric force. Orbital motion of larger, bound grains is described analytically using the orbit-averaged Hamiltonian approach and consists of orbital plane precession at a fixed semi-major axis, accompanied by the periodic variations of the inclination and eccentricity (the latter may approach unity in some cases). A more detailed analysis of the combined effect of gas and Coulomb drag shows it is possible to reduce particle semi-major axes, but that the degree of orbital decay is limited (a factor of several at best) by passages through atomic and molecular clouds, which easily eject small particles.

40 pages, 14 figures, 1 table, accepted to ApJ

References in corpus (3)

• Interstellar Dust Inside and Outside the Heliosphere
• The Formation of the Oort Cloud in Open Cluster Environments
• Perspectives on Interstellar Dust Inside and Outside of the Heliosphere

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• Changes in orientation and shape of protoplanetary discs moving through an ambient medium
• Dust Formation By Failed Supernovae
• On how the optical depth tunes the effects of ISM neutral atom flow on debris disks
• Geodesic motion in the vacuum C-metric
• Orbital evolution under action of fast interstellar gas flow
• Probing Oort Cloud and Local Interstellar Medium Properties via Dust Produced in Cometary Collisions
• Influence of fast interstellar gas flow on dynamics of dust grains
• On the stability of dust orbits in mean motion resonances with considered perturbation from an interstellar wind
• Orbital evolution under the action of fast interstellar gas flow with non-constant drag coefficient
• Is the Infrared Background Excess Explained by the Isotropic Zodiacal Light from the Outer Solar System?
• Dust particles in mean motion resonances influenced by an interstellar gas flow