Out-of-plane equilibria in the perturbed photogravitational restricted three-body problem with Poynting-Robertson (P-R) drag

We consider the primaries of the circular restricted three-body problem (CR3BP) to be luminous and study the effects of small perturbations in the Coriolis and centrifugal forces together with Poynting-Robertson (P-R) drag from both primaries on the motion of an infinitesimal body near the out-of-plane equilibrium points (OEPs). It is found that these points appear in pairs and, depending on the values of the parameters of the system, their number may be zero, two, L(6,7) or four, L(6,7,8,9). It is observed that the positions of these points depend on all the system parameters except small perturbation in the Coriolis force. This has been shown for binary systems RW-Monocerotis and Krüger-60. The linear stability of the out-of-plane equilibria is also studied and it is found that stability of some of these points significantly depends on the perturbing forces. Specifically, the motion of the infinitesimal body around the equilibria is conditionally stable only at points L(6) and L(7) in the absence of P-R drag effect in both binary systems. However, all the equilibria are unstable in the presence of the P-R drag effect. We may conclude therefore, that P–R effect destroys stability of the out-of-plane equilibria.