2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190255A brief review of the stability of rotating relativistic stars is followed by a more detailed discussion of recent work on an instability of r-modes, modes of rotating stars that have axial parity in the slow-rotation limit. These modes may dominate the spin-down of neutron stars that are rapidly rotating at birth, and the gravitational waves they emit may be detectable.14 pages PTPTeX v.1.0. Contribution to proceedings of the 1999 Yukawa International SeminarGeneral Relativity and Quantum CosmologyAstrophysicstext