Year: 2022
Type: article
Abstract: The size of a disk encodes important information about its evolution. Combining new Submillimeter Array observations with archival Atacama Large Millimeter/submillimeter Array data, we analyze millimeter continuum and CO emission line sizes for a sample of 44 protoplanetary disks around stars with masses of 0.15–2 M ⊙ in several nearby star-forming regions. Sizes measured from 12CO line emission span from 50 to 1000 au. This range could be explained by viscous evolution models with different α values (mostly of 10−4–10−3) and/or a spread of initial conditions. The CO sizes for most disks are also consistent with MHD wind models that directly remove disk angular momentum, but very large initial disk sizes would be required to account for the very extended CO disks in the sample. As no CO size evolution is observed across stellar ages of 0.5–20 Myr in this sample, determining the dominant mechanism of disk evolution will require a more complete sample for both younger and more evolved systems. We find that the CO emission is universally more extended than the continuum emission by an average factor of 2.9 ± 1.2. The ratio of the CO to continuum sizes does not show any trend with stellar mass, millimeter continuum luminosity, or the properties of substructures. The GO Tau disk has the most extended CO emission in this sample, with an extreme CO-to-continuum size ratio of 7.6. Seven additional disks in the sample show high size ratios (≳4) that we interpret as clear signs of substantial radial drift.
Source: The Astrophysical Journal
Institutions: Center for Astrophysics Harvard & Smithsonian, Leiden University, University of Leicester, Leiden Observatory, Institute of Astronomy and Astrophysics, Academia Sinica, National Tsing Hua University, Academia Sinica, Max Planck Institute for Astronomy, University College London, University of Wisconsin–Madison, Centre National de la Recherche Scientifique, Université Paris-Saclay, Institut d'Astrophysique Spatiale
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, Alexander von Humboldt-Stiftung, National Radio Astronomy Observatory, Academia Sinica, Bundesministerium für Bildung und Forschung, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, Smithsonian Astrophysical Observatory, Science and Technology Facilities Council, National Institutes of Natural Sciences
OpenAlex ID: W4226069086