2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/11989We show that the free precession of a triaxial body can naturally explain the anomalously rapid change of the X-ray pulse profile of Her X-1 observed by the HEAO-1 in September 1978 without requiring a large change in the moment of inertia.4 pages with 5 eps figures, l-aa.sty+epsf.sty, Astron. Astrophys. in press, replaced with a revised version with typos corrected and 1 figure changedAstrophysicstext