Testing dust trapping in the circumbinary disk around GG Tauri A

Context. The protoplanetary disk around the GG Tau A binary system is one of the most studied young circumbinary disk, and it has been observed at many different wavelengths. Observations of the dust continuum emission at sub-mm/mm wavelengths have detected a dust ring located between 200 AU and 300 AU from the center of mass of the system. According to the classical theory of tidal interaction between a binary system and its circumbinary disk, the measured inner radius of the mm-sized dust ring is significantly larger than the predicted truncation radius, given the observed projected separation of the stars in the binary system (0.25′′, corresponding to ~ 34 AU). A possible explanation for this apparent tension between observations and theory is that a local maximum in the gas radial pressure is created at the location of the center of the dust ring in the disk as a result of the tidal interaction with the binary. An alternative scenario invokes the presence of a misalignment between the disk and the stellar orbital planes.