Thermonuclear burning ignition and propagation in surface layers of neutron stars. 2. Multi-zone model with mass inflow

To study thermonuclear burning ignition and propagation in surface layers of neutron stars we develop a multi-zone model of a thin layer dynamics. It takes into account evolution of the layer composition due to flow of matter (accretion) and thermonuclear reactions. Two simplest variants—one-zone single-component and two-zone two-component models—enable to study qualitatively X-ray bursts dynamics for accretion of pure helium matter or hydrogen, helium and heavier elements mixture. Temporal parameters of X-ray bursts are determined from these models. They are compared with observational data.