Orbital effects of a monochromatic plane gravitational wave with ultra-low frequency incident on a gravitationally bound two-body system

Understand

We analytically compute the long-term orbital variations of a test particle orbiting a central body acted upon by an incident monochromatic plane gravitational wave.

• We assume that the characteristic size of the perturbed two-body system is much smaller than the wavelength of the wave.
• Moreover, we also suppose that the wave's frequency is much smaller than the particle's orbital one.
• We make neither a priori assumptions about the direction of the wavevector nor on the orbital geometry of the planet.