On the influence of asteroid deformations during close approach to the Earth on its rotational and orbital dynamics

During close approach to the Earth, the asteroid’s figure may experience noticeable deformations. Numerical experiments were used to examine the effect of changes in the asteroid’s figure on the magnitudes of disturbances arising in its rotational motion during approach and on the orbital dynamics by changing the magnitude of the Yarkovsky effect. It was found that due to tidal deformation of the asteroid’s figure during approach, accompanied by a change in the moments of inertia, the magnitudes of disturbances in rotation are significantly higher than in the case of an unchanged figure. It was shown that a change of 10–25% in the inertial parameters of the asteroid (99942) Apophis during its approach to the Earth in 2029 leads to a 2–4-fold increase in the sizes of the regions in which the rotational period and the magnitude of the angle characterizing the inclination of the rotation axis to the orbital plane may change. Perturbations in the rotation of the asteroid lead to a change in the parameter A2, which characterizes the Yarkovsky effect, for the size of the region of change of which a similar conclusion is made.