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Precessing accretion discs have long been suggested as explanations for the long periods observed in a variety of X-ray binaries, most notably Her X-1/HZ Her. We show that an instability of the discs response to the radiation reaction force from the illumination by the central source can cause the disc to tilt out of the orbital plane and precess in something like the required manner. The rate of precession and disc tilt obtained for realistic values of system parameters compare favourably with the known body of data on X-ray binaries with long periods. We explore other possible types of behaviour than steadily precessing discs that might be observable in systems with somewhat different parameters. At high luminosities, the inner disc tilts through more than 90 degrees, i.e. it rotates counter to the usual direction, which may explain the torque reversals in systems such as 4U 1626-67.
The properties of wind accretion in symbiotic X-ray binaries (SyXBs) consisting of red-giant and magnetized neutron star (NS) are discussed. The spin-up/spin-down torques applied to NS are derived based on a hydrodynamic theory of quasi-spherical acc
We aim to examine the detailed disc structure that arises in a misaligned binary system as a function of the disc aspect ratio h, viscosity parameter alpha, disc outer radius R, and binary inclination angle gamma_F. We also aim to examine the conditi
We discuss two important instability mechanisms that may lead to the limit-cycle oscillations of the luminosity of the accretion disks around compact objects: ionization instability and radiation-pressure instability. Ionization instability is well e
we study the long-term evolution of the accretion disk around the neutron star in Be/X-ray binaries. We confirm the earlier result by Hayasaki & Okazaki (2004) that the disk evolves via a two-stage process, which consists of the initial developing st
From hot, tenuous gas dominated by Compton processes, to warm, photoionized emission-line regions, to cold, optically thick fluorescing matter, accreting gas flows in X-ray binaries span a huge portion of the parameter space accessible to astrophysic