Abstract
It was recently proposed that there exist stable supersymmetric phases for finite temperature superstings. This issue was investigated using an effective supergravity which takes into account massive winding modes. Such a theory admits BPS solutions that do not suffer from Hagedorn-type instabilities. We extend several aspects of this work. First we restrict to the real-field sector of the theory and allow, in general, for unequal right and left winding fields. Then, by further specializing to type-II theories (IIA, IIB and a self-dual hybrid) we construct the most general 1/2-BPS solution and reveal several new features arising in various consistent truncations. In the heterotic case we investigate the general properties of the solution which is presented in a closed form in the limit of infinitely large left-winding field.