Diurnal Yarkovsky effect as a source of mobility of meter-sized asteroidal fragments I. Linear theory

A linear theory for the heat conduction in a spherical, solid and rotating body illuminated by solar radiation is developed in detail. The principal aim is to compute the recoil force, due to thermally reemitted radiation, which is commonly known as the “Yarkovsky force”. We concentrate on the thermal effect which depends on the rotational period of a body rather than on the period of revolution around the Sun and deal with the general case of an arbitrary obliquity of the spin axis to the orbital plane. This “diurnal” thermal effect is considered to be an important source of mobility for meter-sized stony asteroidal fragments in the main belt. We compare our results with those of previous authors and show that the results of Peterson (1976) are accurate for meter-sized asteroidal bodies (although he used unrealistically long rotation periods).