Distance of the sub-mm ring R_mm from the gapradius R_gap as a function of planet mass for all the simulations. The gap radius is estimated from the ¹³ CO J = 3-2 emission, whereas the ring radius is obtained from the maximum in sub-mm (850 μm) continuum emission outside the gap radius. The ring distance is defined as the ring radius minus the gap radius. Circles, squares, and diamonds indicate quantities retrieved from images convolved with a 0.03^′′, 0.08^′′, and 0.15^′′ beam, respectively, for sources located at a distance of 150 pc. The dashed green line shows a linear fit obtained for this relation in log–log space. The blue dashed-dotted line and brown dashed line indicate the fitting formula by Rosotti et al. (2016) obtained from hydro-simulations with 400 and 3000 planet orbits, respectively, where the gap location was inferred from synthetic scattered light maps.