The Astrophysical Journal (Jan 2023)

Early Planet Formation in Embedded Disks (eDisk). I. Overview of the Program and First Results

  • Nagayoshi Ohashi,
  • John J. Tobin,
  • Jes K. Jørgensen,
  • Shigehisa Takakuwa,
  • Patrick Sheehan,
  • Yuri Aikawa,
  • Zhi-Yun Li,
  • Leslie W. Looney,
  • Jonathan P. Williams,
  • Yusuke Aso,
  • Rajeeb Sharma,
  • Jinshi Sai (Insa Choi),
  • Yoshihide Yamato,
  • Jeong-Eun Lee,
  • Kengo Tomida,
  • Hsi-Wei Yen,
  • Frankie J. Encalada,
  • Christian Flores,
  • Sacha Gavino,
  • Miyu Kido,
  • Ilseung Han,
  • Zhe-Yu Daniel Lin,
  • Suchitra Narayanan,
  • Nguyen Thi Phuong,
  • Alejandro Santamaría-Miranda,
  • Travis J. Thieme,
  • Merel L. R. van ’t Hoff,
  • Itziar de Gregorio-Monsalvo,
  • Patrick M. Koch,
  • Woojin Kwon,
  • Shih-Ping Lai,
  • Chang Won Lee,
  • Adele Plunkett,
  • Kazuya Saigo,
  • Shingo Hirano,
  • Ka Ho Lam,
  • Shoji Mori

DOI
https://doi.org/10.3847/1538-4357/acd384
Journal volume & issue
Vol. 951, no. 1
p. 8

Abstract

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We present an overview of the Large Program, “Early Planet Formation in Embedded Disks (eDisk),” conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The ubiquitous detections of substructures, particularly rings and gaps, in protoplanetary disks around T Tauri stars raise the possibility that at least some planet formation may have already started during the embedded stages of star formation. In order to address exactly how and when planet formation is initiated, the program focuses on searching for substructures in disks around 12 Class 0 and 7 Class I protostars in nearby (<200 pc) star-forming regions through 1.3 mm continuum observations at a resolution of ∼7 au (0.″04). The initial results show that the continuum emission, mostly arising from dust disks around the sample protostars, has relatively few distinctive substructures, such as rings and spirals, in marked contrast to Class II disks. The dramatic difference may suggest that substructures quickly develop in disks when the systems evolve from protostars to Class II sources, or alternatively that high optical depth of the continuum emission could obscure internal structures. Kinematic information obtained through CO isotopologue lines and other lines reveals the presence of Keplerian disks around protostars, providing us with crucial physical parameters, in particular, the dynamical mass of the central protostars. We describe the background of the eDisk program, the sample selection and their ALMA observations, and the data reduction, and we also highlight representative first-look results.

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