Causality Principle for a Reissner–Nordstrom Field in the RTG: The Small-Charge Case $q^2 \le m^2$

We analyze the validity of the causality principle for the external electrovac solution generated by a static spherically symmetric and electrically charged body in the relativistic theory of gravity with a vanishing graviton mass, i.e., the Reissner–Nordstrom solution. We show that this principle restricts values of the constant in the external solution and also sets a lower bound for the source radius. We demonstrate that the external field of superdense star configurations satisfies the causality principle.