Mass transfer has switched the mass ratio!
If one of the binary stars expands (e.g., due to evolution into a red giant) beyond
its Roche lobe, the tidal pull of the other
star can lead to direct mass exchange.
Effective binary potential
Much of the analytic theory of RLOF was laid out in Lubow & Shu in 1975...
From this work they estimated the stream width, exit angle, and velocity profile.
