Dual-wavelength ALMA Observations of Dust Rings in Protoplanetary Disks

Feng Long, Paola Pinilla, Gregory J. Herczeg, Sean M. Andrews, Daniel Harsono, Doug Johnstone, Enrico Ragusa, Ilaria Pascucci, David J. Wilner, Nathan Hendler, Jeff Jennings, Yao Liu, Giuseppe Lodato, Francois Menard, Gerrit Van De Plas, Giovanni Dipierro

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


We present new Atacama Large Millimeter/submillimeter Array observations for three protoplanetary disks in Taurus at 2.9 mm and comparisons with previous 1.3 mm data both at an angular resolution of ∼0.″1 (15 au for the distance of Taurus). In the single-ring disk DS Tau, double-ring disk GO Tau, and multiring disk DL Tau, the same rings are detected at both wavelengths, with radial locations spanning from 50 to 120 au. To quantify the dust emission morphology, the observed visibilities are modeled with a parametric prescription for the radial intensity profile. The disk outer radii, taken as 95% of the total flux encircled in the model intensity profiles, are consistent at both wavelengths for the three disks. Dust evolution models show that dust trapping in local pressure maxima in the outer disk could explain the observed patterns. Dust rings are mostly unresolved. The marginally resolved ring in DS Tau shows a tentatively narrower ring at the longer wavelength, an observational feature expected from efficient dust trapping. The spectral index (α mm) increases outward and exhibits local minima that correspond to the peaks of dust rings, indicative of the changes in grain properties across the disks. The low optical depths (τ ∼ 0.1-0.2 at 2.9 mm and 0.2-0.4 at 1.3 mm) in the dust rings suggest that grains in the rings may have grown to millimeter sizes. The ubiquitous dust rings in protoplanetary disks modify the overall dynamics and evolution of dust grains, likely paving the way toward the new generation of planet formation.

Original languageEnglish (US)
Article number36
JournalAstrophysical Journal
Issue number1
StatePublished - Jul 20 2020

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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