Nonstatic charged spheres admitting a conformal Killing vector

Abstract

Exact, nonstatic, spherically symmetric solutions of the Einstein–Maxwell equations are found for self-gravitating charged spheres under the assumption of the existence of a conformal Killing vector. Solutions are matched to the Reissner–Nordstrom metric and it is found that as a consequence of the junction conditions, the material must be anisotropic. The radius of the sphere for static distributions corresponds to the radius of the unstable null circular orbit of the Reissner–Nordstrom geometry.