Poynting-Robertson effect and perihelion motion

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 $\vec{v} / c$, where $\vec{v}$ 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 $Q'_{\rm pr}$, 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