Motion of Dust Particles under the Influence of a Latitudinally Dependent Force
Abstract
The Kelperian motion of dust particles in the solar system is mainly influenced by the electromagnetic and plasma PoyntingRobertson drag. The first force is isotropic while the second one shows latitudinal variations due to the observed differences of the solar wind parameters in the ecliptic plane and over the solar poles. Close to the Sun other effects become important, e.g. sublimation and sputtering, as well as for submicron particles Lorentz scattering has to be taken into account. These forces are very weak for dust grains of moderate size (10 100 µ) not too close (>0.03 AU) to the Sun and are neglected here. Assuming that the general form of the latidudinally dependent force is a series expansion in Legendre polynomials, we have studied the averaged equations of motion for the classical elements and found the first integral of them. The general character of motion is the same as for the classical PoyntingRobertson drag: particles spiral towards the Sun. The new features in the orbital evolution under the latitudinally dependent force as compared with the isotropic PoyntingRobertson drag are:
(1)
not only the semimajor axisa and the eccentricity ∊ but also the argument of the perihelion ω varies with time,
(2)
the rate of change ofa, ∊, ω depends on the inclination. An example of particle trajectories in the phase space of elements is presented.
 Publication:

Celestial Mechanics and Dynamical Astronomy
 Pub Date:
 August 1994
 DOI:
 10.1007/BF00692103
 Bibcode:
 1994CeMDA..59..375S
 Keywords:

 Celestial Mechanics;
 Cosmic Dust;
 Orbits;
 PoyntingRobertson Effect;
 Solar Radiation;
 Astronomical Models;
 Equations Of Motion;
 Kepler Laws;
 Legendre Functions;
 Lorentz Force;
 Numerical Integration;
 Astrophysics;
 Dust particles;
 nonisotropic forces