For a scenario of a close flyby of a compact star near a spinning black hole. we provide analytical and numerical estimates for the shift of trajectory periastron due to relativistic (beyond post-Newtonian) effects. More specifically. we derived a generalized expression (not limited to quasi-circular or elliptical orbits) directly linking the periastron shift and the spin of the black... https://foldlyers.shop/product-category/essentials-kits/