Solar wind and motion of dust grains

TL;DR

This paper derives a relativistically covariant equation of motion for interplanetary dust particles under solar wind influence, revealing new effects on orbital evolution and perihelion shift that differ from traditional models.

Contribution

It introduces a comprehensive covariant model for dust particle dynamics under solar wind, including non-radial velocities and mass change, extending previous simplified treatments.

Findings

Solar wind causes perihelion shift of dust particles.

The model differs from the Poynting-Robertson effect in key aspects.

Orbital evolution depends on the parent body's ejection timing.

Abstract

Action of solar wind on arbitrarily shaped interplanetary dust particle is investigated. The final relativistically covariant equation of motion of the particle contains both orbital evolution and change of particle's mass. Non-radial solar wind velocity vector is also included. The covariant equation of motion reduces to the Poynting-Robertson effect in the limiting case when spherical particle is treated, the speed of the incident solar wind corpuscles tends to the speed of light and the corpuscles spread radially from the Sun. The results of quantum mechanics have to be incorporated into the physical considerations, in order to obtain the limiting case. The condition for the solar wind effect on motion of spherical interplanetary dust particle is $\vec{p}'_{out}$ $=$ (1 $-$ $\sigma'_{pr} / \sigma'_{tot}$) $\vec{p}'_{in}$, where $\vec{p}'_{in}$ and $\vec{p}'_{out}$ are incoming and outgoing radiation momenta (per unit time) measured in the proper frame of reference of the particle; $\sigma'_{pr}$ and $\sigma'_{tot}$ are solar wind pressure and total scattering cross sections. Real flux density of solar wind energy produces shift of perihelion of interplanetary dust particles. This result significantly differs from the standard treatment of the action of the solar wind on dust particles, when analogy with the Poynting-Robertson effect is stressed. Moreover, the evolution of the shift of perihelion depends on orbital position of the parent body at the time of ejection of the particle.