Abstract:
The ringed substructures observed in protoplanetary disks are key sites for planetesimal formation and the subsequent assembly of planetary cores. Understanding the dust surface density, particle properties, size distribution, and turbulence levels within these rings is critical to deciphering how and where planets form.
In this talk, I will present insights into the dust content of ring substructures across multiple protoplanetary disks from multi-wavelength (sub)mm continuum observations. Our findings reveal evidence for mm particles concentrated within the rings. By linking grain sizes to the fragmentation threshold and turbulence constraints in seven disks, we show that grains in these regions are likely more fragile than traditionally assumed (with fragmentation velocities only $v_\text{frag} \sim 1$ m/s). Furthermore, by analyzing azimuthal intensity variations, we estimate the dust scale heights of six disks with double rings located in different radii, uncovering a consistent pattern: higher dust scale heights in inner rings compared to outer ones, potentially suggesting stronger turbulence in the inner disk regions. These results align with the current theoretical framework of vertical shear instability and provide new clues about how dust substructures assist with planet formation.
