Dynamics of neutral small particles

Abstract

ABSTRACTThe dynamics of small grains are reviewed when the radiation pressure forces are added to the gravitational attraction.In the first section we attempt to summarize the studies dealing with the interaction matter - radiation. The problem consists in the computation of the momentum transfer between a grain and the radiation field. The flie's theory of scattering is used for this purpose and the results come out as the value of the ratio of the radiation pressure force to the gravitational force for various material of different sizes.The motion of a grain in an heliocentric orbit is discussed through the second section and includes conditions for a particle to be ejected from the solar system, abrupt change of the orbital elements due to fragmentation along with continuous variation generated by sublimation and sputtering. Likewise the Poynting- Robertson drag is considered and some results are given concerning the lagrangian points L4 and L5 when radiation forces are taken into account.The last section deals with the motion of a grain about a planet. The solution of this problem has recently been updated and the orbital evolution of a grain is presented for a sphericla planet. In order to make the solution relevant for the planetary rings it is adapted to allow for the planet's oblateness.