Can a neutron star undergo a direct transition between the states of ejector and accretor skipping the state of propeller? I. Approximation of non-magnetized accretion flow

Abstract

We discuss evolution of a neutron star in the massive binary system in terms of evolutionary chain of its states: ejector, propeller and accretor. We show that a direct transition between the states of ejector and accretor (without the propeller state) can take place only in the systems with relatively low-velocity stellar wind of the massive component in case of formation of the Keplerian accretion disk of low viscosity.