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Today's Colloquium: Zooming in on the planet-forming zones of disks: Sweet Results from ALMA

Submitter: Ewine van Dishoeck
Description: Editor's note: Do not miss this opportunity to hearken(*) to the next President of the IAU!

Protoplanetary disks are the birthplaces of planets, but the spatial resolution at long wavelengths has so far been insufficient to resolve the critical 5-30 AU region where they are formed. ALMA now allows us to zoom in to nearby disks and probe the physical and chemical structure associated with planet formation.

This talk will provide an overview of recent work by our group and colleagues on observations and models of protoplanetary disks around young stars in various stages of evolution. Early ALMA results include evidence for rotationally supported disks in the deeply embedded stage, the detection of organic molecules (including sugar) and water in forming disks, and the first images of the CO snowline in mature disks.

Special attention will be given to transitional disks, which are a subset of disks with evidence for sharp-rimmed cavities (gaps or holes) in their inner part but with otherwise normal outer disks. These disks are called 'transitional' because they are thought to represent the evolutionary phase from the gas-rich protoplanetary disk to the gas-poor debris disk stage. They are the best candidate sources for harboring just-formed giant planets.

ALMA allows imaging of both the gas and dust in these disks, with gas cavities found to be significantly smaller than those of the dust, providing constraints on the properties of the young planets. The surprising discovery of huge asymmetric dust traps ('planetesimal or Kuiper-Belt factory') will be highlighted.

(*) To hearken (hark, harken): To listen attentively
Copyright: Ewine van Dishoeck
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