We discuss the low-energy effective string theory when moduli of the compactified manifold are present. Assuming a nontrivial coupling of the moduli to the Maxwell tensor, we find a class of regular black-hole solutions. Both the thermodynamical and the geometrical structure of these solutions are discussed.

• Received 21 June 1993

DOI:https://doi.org/10.1103/PhysRevD.48.5536