When dealing with Binary systems and their evolution and mass transfers in the systems, why are effective potential and equipotential surfaces point of interest? The one which is called the Roche lobe. How is the effective field at the points on surface and around ? Masses are said to be gravitationally bounded if they are inside these surface what does it mean for them to be gravitationally bounded and what if they go beyond these surfaces and from different region of it ?
How do I mathematically construct one of such surface ?