First results from the ALMA Large Program "Small-scale substructure in protoplanetary disks"

The process of disk evolution and planet formation will leave an imprint on the distribution of solid particles at different locations in a protoplanetary disk, resulting in a variety of substructure (gaps, rings, spirals, vortices, clumps, etc.) over large and small scales. The role of these small-scale features is fundamental: theory predicts that without substructure large solids would be lost due to radial drift, impeding planetesimal and planet formation. Recent ALMA observations of protoplanetary disks at high spatial resolution show some form of substructure, but to understand the prevalence and diversity of these features in the general disk population we need to go beyond small number statistics with heterogeneous resolution and sensitivity. In this talk, I will discuss the first results from our ALMA Large Program "Small-scale substructure in protoplanetary disks", aimed at characterizing the underlying substructure of a sample of 20 nearby classical disks. These new observations constrain the spatial distribution of solid particles of roughly 1 mm in size with uniform sensitivity and resolution, from dust continuum images in Band 6 (1.3 mm). The exceptional spatial resolution of this survey probes well into the planet-forming zones of disks, in to radius of ~3 AU. I will introduce the details of the survey, present its current status, and discuss our preliminary findings.