Coupled or not coupled, that is the question. An hint on the disc mass

Recent high resolution and high sensitivity observations of protoplanetary discs are showing us peculiar substructures, such as spirals, gaps and horseshoes. Disc instabilities and planets have been proposed to be responsible for their formation. However, their origin is still very debated, in particular it is not clear how their shape depends on the disc mass and on the coupling between the gas and the dust component of the disc. I will present the results of our hydrodynamical modeling of the protoplanetary disc HD135344B (Garufi et al. 2013, van der Marel et al. 2016), that shows a distinctive spiral structure in scattered light and an asymmetric horseshoe in the dust continuum. We performed hydrodynamical and Monte Carlo Radiative Transfer simulations of a protoplanetary disc with two embedded planets, varying the total gas mass of the disc. Furthermore, I will present preliminary results in order to find if it is possible to estimate the total disc mass in protoplanetary discs by the combined hydrodynamical modeling of planet-induced disc substructures observed in scattered light (micron-sized grains) and in the dust continuum (mm-sized grains).