Stability and dynamics of misaligned circumbinary discs

C. A. GIUPPONE; N. CUELLO

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2019

0004-6361

Due to observational biases, circumbinary planet detections are rather rare. In fact, up to now, only a handful of binary systems with planets have been reported (by extit{Kepler} mainly). However, planet formation is expected to occur around binary stars as well. Dynamical studies suggest that most of the circumbinary discs should be coplanar, i.e. the rotation vectors of the binary and the disc are aligned. Interestingly, some recent theoretical works show that under certain conditions circumbinary discs can become polar, which means that the rotation vectors are orthogonal. In this work, we explore how these conditions could be reached and we assess how likely is the disc to become polar with respect to the binary. We present 3D smoothed particle hydrodynamics (SPH) simulations of misaligned discs and follow their resulting alignments. In addition, we study the stability of the extbf{inclined and polar} configurations through N-body simulations. We confirm previous predictions and show that a broad range of configurations lead to polar and retrograde discs. In such cases, the resulting planetary architectures should be polar and retrograde as well. Despite their low probability of detection, we suggest that polar and retrograde (S-type) planets might be rather common around those binary stars that suffered close encounters.