Multi-wavelength Constraints on Dust Dynamics and Size Evolution in Protoplanetary Disk Rings. II. Observational Implications

Spatially resolved dust rings in protoplanetary disks are widely used to infer disk and dust physics from multi-wavelength continuum observations. Their interpretation, however, often neglects grain growth and the evolution of the size distribution, limiting the connection between observed ring profiles and dust-evolution parameters. Building on a physical dust-ring model that includes coagulation and fragmentation, we develop a Bayesian inference framework that jointly incorporates radiative transfer and finite angular resolution. When applied to two rings in HD 163296 and two in LkCa 15, our framework yields gas-dependent estimates of the key dust-evolution parameters such as turbulence strength α and the fragmentation velocity v frag in a self-consistent way. Most rings admit both a low- α, low- v frag branch with small grains, and a higher- α, higher- v frag branch with larger grains. Typical low- α branches have α about10-5 -- 10-4 and fragmentation velocities of order cm s-1 level, whereas the higher- α branches reach α about10-3 -- 10-2 and fragmentation velocities of a few to 20 m s-1. The observed broad and wavelength-dependent profiles near the ring peaks can be reproduced by intrinsically narrow dust rings. This new framework offers a more direct route from multi-wavelength continuum data to the microphysics of dust growth and trapping---a connection that can be robustly tested with future high-resolution observations at longer wavelengths.