Schematic of a binary system, consisting of a primary star of mass M₁, and a secondary of mass M₂ orbiting with an angular speed ω, where the centre of mass of the binary system is located at . The primary and secondary are respectively located at r₁ and r₂ with respect to . Mass is ejected from the inner-Lagrangian, ℒ₁, point (yellow star), located at r_ℒ1 with respect to the primary’s mass centre, . Material falls towards the secondary (dashed line) and is accreted onto its surface (or at the edge of an accretion disc) at A, situated at r_acc with respect to its mass centre, . Alternatively, material falls onto the primary’s surface (dotted line), landing at B, located at with respect to . The unit vectors ê_r and ê_t point along the line joining the two stars (towards the secondary), and perpendicular to this line, respectively, and ν is the true anomaly.