A large fraction of the protoplanetary disks observed with ALMA display multiple well-defined and nearly perfectly circular rings in the continuum , in many cases with substantial peak-to-valley contrast .
The DSHARP campaign shows that several of these rings are very narrow in radial extent .
In this paper we test the hypothesis that these dust rings are caused by dust trapping in radial pressure bumps , and if confirmed , put constraints on the physics of the dust trapping mechanism .
We model this process analytically in 1D , assuming axisymmetry .
By comparing this model to the data , we find that all rings are consistent with dust trapping .
Based on a plausible model of the dust temperature we find that several rings are narrower than the pressure scale height , providing strong evidence for dust trapping .
The rings have peak absorption optical depth in the range between 0.2 and 0.5 .
The dust masses stored in each of these rings is of the order of tens of Earth masses , though much ambiguity remains due to the uncertainty of the dust opacities .
The dust rings are dense enough to potentially trigger the streaming instability , but our analysis can not give proof of this mechanism actually operating .
Our results show , however , that the combination of very low \alpha _ { \mathrm { turb } } \ll 5 \times 10 ^ { -4 } and very large grains a _ { \mathrm { grain } } \gg 0.1 \mathrm { cm } can be excluded by the data for all the rings studied in this paper .