On out of plane equilibrium points in photo-gravitational restricted three-body problem

We have investigated the out of plane equilibrium points of a passive micron size particle and their stability in the field of radiating binary stellar systems Krüger -60, RW-Monocerotis within the framework of photo-gravitational circular restricted three-body problem. We find that the out of plane equilibrium points ( L i , i = 6, 7, 8, 9) may exist for range of β 1 (ratio of radiation to gravitational force of the massive component) values for these binary systems in the presence of Poynting-Robertson drag (hereafter PR-drag). In the absence of PR-drag, we find that the motion of a particle near the equilibrium points L 6,7 is stable in both the binary systems for a specific range of β 1 values. The PR-drag is shown to cause instability of the various out of plane equilibrium points in these binary systems.