In this paper, we investigate the action of solar wind on an arbitrarily shaped interplanetary dust particle. The final relativistically covariant equation of motion of the particle also contains the change of the particle’s mass. The 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 a spherical particle is treated, when the speed of the incident solar wind corpuscles tends to the speed of light and when 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. If the solar wind affects the motion of a spherical interplanetary dust particle, then . Here, p′in and p′out are the incoming and outgoing radiation momenta (per unit time), respectively, measured in the proper frame of reference of the particle, and and are the solar wind pressure and the total scattering cross‐sections, respectively. An analytical solution of the derived equation of motion yields a qualitative behaviour consistent with numerical calculations. This also holds if we consider a decrease of the particle’s mass. Using numerical integration of the derived equation of motion, we confirm our analytical result that the non‐radial solar wind (with a constant value of angle between the radial direction and the direction of the solar wind velocity) causes outspiralling of the dust particle from the Sun for large values of the particle’s semimajor axis. The non‐radial solar wind also increases the time the particle spirals towards the Sun. If we consider the periodical variability of the solar wind with the solar cycle, then there are resonances between the particle’s orbital period and the period of the solar cycle.

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We investigate the effect of solar wind and solar electromagnetic radiation on the dynamics of spherical cosmic dust particles. We also consider the non-radial component of the solar wind velocity, in the reference frame of the Sun. We apply the equation of motion to the motion of dust grains near commensurability resonances with a planet -mean motion orbital resonance (MMR; a particle is in resonance with a planet when the ratio of their mean motions is approximately the ratio of two small integers) -and possible capture of the grains in the resonances. Up to now, only nonspherical grains, under action of the electromagnetic radiation of the central star, were known to exhibit an increase of semimajor axis before capture into the MMR. This paper shows that the same result can be generated by the non-radial component of the solar wind even for spherical dust particles. Spherical dust grains enable the treatment of the problem in an analytic way (at least partially), which is not the case for the effect of electromagnetic radiation on nonspherical dust grains. The situation treated in the paper presents the second known case when resonant trapping of a cosmic body occurs for diverging orbits. The paper presents the first case of secular evolution of the eccentricity of a body captured in the resonance derived in an analytic way for a body characterized by a diverging orbit.

Eccentricity evolution of a dust particle in a mean motion orbital resonance with a planet in circular orbit is investigated. The action of solar electromagnetic and corpuscular radiation, including non-radial components of the solar wind velocity, is taken into account. Various types of eccentricity evolution depend on the angle between the radial direction and the direction of the solar wind velocity. The evolution changes at the analytically derived angles. Its application to exosolar systems is included.

Aerosol particles spread in the atmosphere play an important role in solar light scattering and thus co-determine the sky radiance/luminance pattern as well as diffuse irradiances/illuminances at the ground. The particular influence is given by their optical properties and by their distribution in the atmosphere. The dependence of the aerosol extinction coefficient on altitude is usually described by the exponential law, which results from averaging of a large amount of aerosol realizations. This is also frequently the case of simulating of the solar diffuse radiance/luminance distribution over the sky, when it is based on solving the radiative transfer problem. However, the aerosol vertical profile can sometimes be significantly different from the exponential one. Mainly in the urban environment, the aerosol is often well-mixed within the atmospheric boundary layer, so its volume extinction coefficient is almost constant there. This work investigates how such different profiles affect the clear sky radiance pattern and consequently also the ground-based horizontal diffuse irradiance. The numerical simulations reveal that the discrepancies are negligible in practice. So it appears that the aerosol vertical distribution does not play any important role in sky radiance calculations and the standard exponential law is general enough to cover also various specific aerosol conditions.

The effect of stellar electromagnetic radiation on the motion of homogeneous spherical dust particles, the Poynting-Robertson (P-R) effect, is investigated. The effect already produces a shift of pericenter/perihelion in the accuracy to the first order in u/c, where u is velocity of the particle with respect to the source of radiation and c is the speed of light. The advancement of pericenter occurs due to the fact that the P-R effect depends on radiation pressure efficiency factor Q pr , which is a function of optical properties of the particle. The particle orbiting a star moves in various distances from the star and the particle optical properties may vary with the distance, as they are functions of temperature.

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