Event

Non-extremal black holes such as the astrophysical black holes we encounter in the sky remain mysterious objects. As solutions to general relativity, they possess certain invariants. We extend prior investigations of so-called hot attractor black holes to higher dimensions and add a scalar potential. In addition to the event and Cauchy horizons, when we complexify the radial coordinate, non-extremal black holes generically have additional horizons. We prove that the product of all of the horizon areas is independent of variations of the asymptotic moduli further generalizing the attractor mechanism for extremal black holes and derive new invariant quantities. We also outline the derivation of horizon invariants for stationary backgrounds such as Kerr–Newman and speculate on the meaning of the entropy associated to the inner horizon.