Influence of Asteroid Shape Deformations When Approaching the Earth on Rotational State Disturbances and the Value of the Yarkovsky Effect

Using numerical experiments, an analysis was made of the influence of changes in the shape of the asteroid on the magnitude of disturbances occurring in its rotational motion during close approach to the Earth. The influence of perturbations in the rotation of an asteroid (changes in the period and orientation of the rotation axis) on the orbital dynamics is considered by changing the magnitude of the Yarkovsky effect. It has been established that during tidal deformation of the asteroid’s figure due to its approach to the Earth, accompanied by a change in the moments of inertia, the magnitude of the perturbations in rotation is significantly higher than in the case of an unchanged figure. It has been shown that a 10–25% change in the inertial parameters of the asteroid (99 942) Apophis during its approach to the Earth in 2029 leads to a 2–4-fold increase in the size of the regions in which the rotation period and the angle characterizing the inclination of the rotation axis to the orbital plane can change. Perturbations in the rotation of the asteroid lead to a change in the parameter A₂, characterizing the Yarkovsky effect. The size of the region of change of parameter A₂ in the presence of deformations in the asteroid’s figure also increases significantly compared to the case of an unchanged figure.