Circumstellar and circumbinary discs in eccentric stellar binaries

We study the existence of stable trajectories, where gas could accumulate to form accretion discs, around stars that form binary systems in eccentric orbits. Since the potential is time dependent, no fixed, periodic, close orbits exist. Instead, we search for invariant loops: closed curves that change shape in synchronism with the binary orbital phase. Non-intersecting loops can provide the scaffolding for circumstellar and circumbinary discs in these systems. We investigate the range of regions in phase space where these non-intersecting loops can exist and find this to depend on both, the mass ratio of the stars and their orbital eccentricity, with a strong dependence on the latter. The recent discovery of planets within close binary systems makes this work very relevant.