Homothetic motions of spherically symmetric space–times

The homotheties of spherically symmetric space–times admitting maximal isometry groups larger than SO(3) are found along with their metrics, using the homothety equations and without imposing any restriction on the stress-energy tensor. It turns out that there are either 11 or 7 or 5 homotheties. For the space–times with SO(3) as a maximal group, solution is provided in the form of derivatives of metric coefficients, which then requires a further classification, for example, according to different types of stress-energy tensor, as has been done by Eardley [Commun. Math. Phys. 37, 287 (1974)], Cahill and Taub [Commun. Math. Phys. 21, 1 (1971)], and McIntosh [Phys. Lett. A 50, 429 (1975)].