Dynamical Evolution of Circumbinary Disks and Embedded Planets

The success of the Kepler space telescope in detecting planets in circumbinary orbits (also known as P-type binaries) strongly suggests that planet formation around binary stars is robust and planets of a variety of sizes and orbital configurations may exist in such dynamically complex environments. Accurate modeling of Kepler data has indicated that the orbits of many of these planets is in close proximity to the boundary of orbital stability (the region around the binary interior to which the orbit of the planet will become unstable), and they all reside between major n:1 mean-motion resonances (MMRs) with their host binaries.

Interestingly, those planets that are close to the boundary of stability are Neptune-mass or slightly larger. A survey of the currently known circumbinary planets (CBPs) further indicates that the orbits of many of these objects are slightly inclined with respect to the plane of the binary, and they precess with rates that place them out of transit for more than 90% of the time. These findings, combined with several unsuccessful attempts in forming CBPs in-situ and close to the orbital stability limit has lent strong support to the idea that almost all currently known CBPs have formed at large distances from their host binaries, and undergone substantial radial migration both during their formation and after they fully formed. Understanding the above-mentioned findings are fundamentally important as not only do they shed light on the evolution and orbital architecture of planets in P-type systems, they also enable us to use circumbinary systems as a laboratory for planet migration to address key questions on the migration of planet and planet-trap in a much broader context. Furthermore, explaining the dynamical evolution and orbital architecture of CBPs will provide us with the theoretical framework necessary to interpret results obtained from future missions, especially the TESS space telescope. With these goals in mind, we propose to carry out a detailed, GPU-based, three-dimensional study of the migration and dynamical evolution of planets in circumbinary sytems, considering fully radiative disks, and taking into account the disk evolution as well as its
interaction with planetary bodies. In brief, we propose to

1) Study the evolution of circumbinary nebulae using 3D radiative disk models,
2) Study planet migration in these disks for different orbital inclinations and masses of the planet, and
3) Study the capture of CBPs between MMRs and in proximity of the binary’s boundary of stability in terms of the physical characteristics of the disk, in particular the size of its inner cavity, and make statistical predictions about planet trapping.