Coplanar circumbinary planets can be unstable to large tilt oscillations in the presence of an inner polar planet

Autor: Childs, Anna C., Martin, Rebecca G., Lepp, Stephen, Lubow, Stephen H., Geller, Aaron M.
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
DOI: 10.3847/2041-8213/acbcc9
Popis: Mutually misaligned circumbinary planets may form in a warped or broken gas disc or from later planet-planet interactions. With numerical simulations and analytic estimates we explore the dynamics of two circumbinary planets with a large mutual inclination. A coplanar inner planet causes prograde apsidal precession of the binary and the stationary inclination for the outer planet is higher for larger outer planet orbital radius. In this case a coplanar outer planet always remains coplanar. On the other hand, a polar inner planet causes retrograde apsidal precession of the binary orbit and the stationary inclination is smaller for larger outer planet orbital radius. For a range of outer planet semi-major axes, an initially coplanar orbit is librating meaning that the outer planet undergoes large tilt oscillations. Circumbinary planets that are highly inclined to the binary are difficult to detect -- it is unlikely for a planet to have an inclination below the transit detection limit in the presence of a polar inner planet. These results suggest that there could be a population of circumbinary planets that are undergoing large tilt oscillations.
Comment: Accepted for publication in ApJL. 7 pages and 4 figures
Databáze: arXiv