Schematic of the central binary and circumbinary disc, as well as the angles used to measure the disc orientation. The binary orbits in the xz-plane, with the angular momentum vector |$\boldsymbol{L}_{\rm b}$| pointing along the positive y-axis and the eccentricity vector |$\boldsymbol{e}_{\rm b}$| pointing along the z-axis. The disc is oriented in 3D space by its angular momentum vector |$\boldsymbol{L}_{\rm disc}$|⁠, where it forms an angle i with the binary angular momentum vector |$\boldsymbol{L}_{\rm b}$|⁠. The grey dashed line denotes the disc’s ‘line of nodes’, where the disc crosses the xz-plane at an angle |$\boldsymbol {\Omega }$| with the eccentricity vector |$\boldsymbol{e}_{\rm b}$|⁠.