Light Deflection around a Spherical Charged Black Hole to Second Order. Multivariate Padé Approximants

The second-order terms for the deflection of light around a large, spherical and charged black hole are derived from the Reissner-Nordström metric using the Lindstedt-Poincaré method to solve the equation of motion of a photon around a compact object. The corrections are performed to establish the expansion in terms of In addition, we obtain multivariate Padé approximants from the expansion of the disruption. We also illustrate how these are a better fit than the original formal Taylor series for the numerical results.