 The mathematical point through which this transfer happens is called the first Lagrangian point.It is not uncommon that the accretion disc is the brightest (and thus sometimes the only visible) element of a binary star.If a star grows outside of its Roche lobe too fast for all abundant matter to be transferred to the other component, it is also possible that matter will leave the system through other Lagrange points or as stellar wind, thus being effectively lost to both components.