Density evolution during the CE phase in our reference simulation. The panels are slices of gas density in the face-on view (top row) and edge-on view (bottom row). The cross symbol indicates the position of the core of the giant star and the plus symbol that of the companion. Panels e, j: zoomed-in views of the central region indicated by the gray boxes in panels c and h, respectively. The actual simulation domain is much larger than the panels shown here. Roche equipotential lines and the positions of the Lagrange points are added in panel e.