Seminario DAS // Exploring gas structure and kinematics in protoplanetary disks

Speaker: Dr. Misato Fukagawa.
Affiliation: Planetary System Formation (Obs.) Group // Tohoku University.

Abstract: Protoplanetary disks are the sites of planet formation, and recent observations at spatial resolutions of approximately 10 au or better have substantially advanced our understanding of their structure and evolution. Near-infrared scattered-light imaging has revealed spiral arms, rings, gaps, and asymmetries on disk surfaces, while millimeter continuum observations trace the distribution of larger dust grains closer to the midplane.

In this talk, I will present ALMA observations of molecular-line emission at high spatial and spectral resolution, including results from a survey of CO emission in 15 disks. Radial variations in rotational velocity trace pressure substructures that tend to be associated with resolved rings and gaps in the dust continuum. Deviations from Keplerian rotation are widespread and morphologically diverse, ranging from localized velocity perturbations to large-scale coherent patterns. Some of these features are consistent with planet-driven wakes, while the physical origins of many others remain to be explored. These results point to a close connection between dust substructures and gas dynamics, and show that departures from smooth, axisymmetric Keplerian rotation are common across the sample.