We show that changes in the orientation of the inner accretion disk of Cygnus X-1 affect the shape of the broad Fe K{alpha} emission line emitted from this object, in such a way that eV-level spectral resolution observations (such as those that will be carried out by the ASTRO-E2 satellite) can be used to analyze the dynamics of the disk. We here present a new diagnosis tool, supported by numerical simulations, by which short observations of Cygnus X-1, separated in time, can determine whether its accretion disk actually processes, and if so, determine its period and precession angle. Knowing the precession parameters of Cygnus X-1 would result in a clarification of the origin of such precession, distinguishing between tidal and spin-spin coupling. This approach could also be used for similar studies in other microquasar systems.

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