Influence of fast interstellar gas flow on dynamics of dust grains

TL;DR

This paper analyzes how fast interstellar gas flows influence the orbital evolution of dust grains, providing analytical solutions for their orbital changes and discussing implications for icy particles in the Solar system.

Contribution

It derives a system of analytical equations describing dust grain orbital evolution under interstellar gas flow, including transformations for different reference planes and specific solutions.

Findings

Orbital elements change periodically or remain constant under gas flow influence.

Solutions applicable to icy particles with radii 1-10 micrometers in orbits 200-3000 AU.

Oscillation periods range from 10^5 to 2 x 10^6 years.

Abstract

The orbital evolution of a dust particle under the action of a fast interstellar gas flow is investigated. The secular time derivatives of Keplerian orbital elements and the radial, transversal, and normal components of the gas flow velocity vector at the pericentre of the particle's orbit are derived. The secular time derivatives of the semi-major axis, eccentricity, and of the radial, transversal, and normal components of the gas flow velocity vector at the pericentre of the particle's orbit constitute a system of equations that determines the evolution of the particle's orbit in space with respect to the gas flow velocity vector. This system of differential equations can be easily solved analytically. From the solution of the system we found the evolution of the Keplerian orbital elements in the special case when the orbital elements are determined with respect to a plane perpendicular to the gas flow velocity vector. Transformation of the Keplerian orbital elements determined for this special case into orbital elements determined with respect to an arbitrary oriented plane is presented. The orbital elements of the dust particle change periodically with a constant oscillation period or remain constant. Planar, perpendicular and stationary solutions are discussed. The applicability of this solution in the Solar system is also investigated. We consider icy particles with radii from 1 to 10 micrometers. The presented solution is valid for these particles in orbits with semi-major axes from 200 to 3000 AU and eccentricities smaller than 0.8, approximately. The oscillation periods for these orbits range from 10^5 to 2 x 10^6 years, approximately.