The Second Post‐Newtonian Motion in Sen Spacetime

Abstract Based on the Sen spacetime, the orbital energy and angular momentum are calculated, and the solution for the motion of a test particle derived to the second post‐Newtonian order. The effect of the Sen black hole's charge on the periastron advance and orbital period is obtained. In particular, it is found that has an influence on perihelion precession at both the first and second post‐Newtonian orders, whereas its effect on the orbital period is confined solely to the second post‐Newtonian order. Finally, the precession of the star S2 is used to constrain our model and the value of is 0.51.