Planet formation and migration is a much studied subject, mostly around single stars. However, stars do not form in isolation and binaries are common.
In the recent decade the number of transit circumbinary planet detection has reached more than a dozen.
The already found circumbinary planets exhibit intriguing similarities in orbit semi-major axis and eccentricity and mass. The planet are orbit just beyond the stability limit at roughly 3 binary separation, planet formation in this region is mostly inhibitied. In order to understand the observation of the circumbinary planet, we will look at planet migration inside the eccentric circumbinary disc in 2d hydrodynamics simulations.
On their path, the planets need to pass through the dense eccentric inner disc, which can trap or even push the planet back onto wider orbits depending on the disc environment.
With simulations we can identify the effective viscosity and disc scale height needed to explain the observation.