Disk surface density during one binary orbit for the standard parameters, see Table 1, after the equilibrium has been reached. The green line indicates the Roche lobes of the stars. In the leftmost image (t₁) the binary is at apastron and the disk is unperturbed. At the binary’s periastron (t₂) the diskis maximally distorted and has the highest eccentricity. After the periastron passage (t₃) two spiral arms are launched that wind inward and dissipate again (t₄). Most of the disk’s mass loss happens in the time frame between t₂ and t₄ that spans 15% of the binary’s period.