interior or exterior to the spirals and showed that planets in the latter configuration with separations $\gtrsim$100 au provided a better match to their shape. The second approach exploits hydrodynamical simulations, which can account for non-linear perturbations, i.e. one planet can drive more than one spiral [e.g., @Dong2015; @Zhu2015; @Juhasz2015; @Pohl2015]. In particular, [some studies have predicted one massive ($\sim$4–15 $M_{\rm{J}}$) planet located exterior to the SAO 206462 spirals [@Fung2015; @Bae2016; @Dong2017]]{}.

@Garufi2013 suggested that one planet of mass from 13 to 5 $M_{\rm{J}}$ located at [17.5–20 au]{} could explain the increase [in]{} the cavity size measured for the small dust grains (28$\pm$6 au) and for the large dust grains [39 to 50 au, @Brown2009; @Andrews2011; @Lyo2011][^2]. This planet could also explain the spiral features. They could not rule out several massive planets inside the cavity, although this hypothesis seems at odds with the presence of diffuse gas. They also rejected several mechanisms not involving perturbing planet(s) [photoevaporation, dust grain growth, magnetorotational instability, @Hollenbach1994; @Dullemond2005; @Chiang2007] [to explain]{} the disk cavity. They finally showed that the disk is globally highly stable [see also @Stolker2016]. Nevertheless, they could not rule out gravitational interactions between SAO 206462 and SAO 206463 [as exciting 