Molecules with ALMA at Planet-forming Scales (MAPS) : a circumplanetary disk candidate in molecular-line emission in the AS 209 Disk
Abstract
We report the discovery of a circumplanetary disk (CPD) candidate embedded in the circumstellar disk of the T Tauri star AS 209 at a radial distance of about 200 au (on-sky separation of 1.″4 from the star at a position angle of 161°), isolated via 13CO J = 2-1 emission. This is the first instance of CPD detection via gaseous emission capable of tracing the overall CPD mass. The CPD is spatially unresolved with a 117 × 82 mas beam and manifests as a point source in 13CO, indicating that its diameter is ≲14 au. The CPD is embedded within an annular gap in the circumstellar disk previously identified using 12CO and near-infrared scattered-light observations and is associated with localized velocity perturbations in 12CO. The coincidence of these features suggests that they have a common origin: an embedded giant planet. We use the 13CO intensity to constrain the CPD gas temperature and mass. We find that the CPD temperature is ≳35 K, higher than the circumstellar disk temperature at the radial location of the CPD, 22 K, suggesting that heating sources localized to the CPD must be present. The CPD gas mass is ≳0.095 M Jup ≃ 30 M ⊕ adopting a standard 13CO abundance. From the nondetection of millimeter continuum emission at the location of the CPD (3σ flux density ≲26.4 μJy), we infer that the CPD dust mass is ≲0.027 M ⊕ ≃ 2.2 lunar masses, indicating a low dust-to-gas mass ratio of ≲9 × 10-4. We discuss the formation mechanism of the CPD-hosting giant planet on a wide orbit in the framework of gravitational instability and pebble accretion.
Citation
Bae , J , Teague , R , Andrews , S M , Benisty , M , Facchini , S , Galloway-Sprietsma , M , Loomis , R A , Aikawa , Y , Alarcón , F , Bergin , E , Bergner , J B , Booth , A S , Cataldi , G , Cleeves , L I , Czekala , I , Guzmán , V V , Huang , J , Ilee , J D , Kurtovic , N T , Law , C J , Le Gal , R , Liu , Y , Long , F , Ménard , F , Öberg , K I , Pérez , L M , Qi , C , Schwarz , K R , Sierra , A , Walsh , C , Wilner , D J & Zhang , K 2022 , ' Molecules with ALMA at Planet-forming Scales (MAPS) : a circumplanetary disk candidate in molecular-line emission in the AS 209 Disk ' , Astrophysical Journal Letters , vol. 934 , no. 2 , 934 . https://doi.org/10.3847/2041-8213/ac7fa3
Publication
Astrophysical Journal Letters
Status
Peer reviewed
ISSN
2041-8205Type
Journal article
Description
Funding J.D.I. acknowledges support from the Science and Technology Facilities Council of the United Kingdom (STFC) under ST/ T000287/1 and an STFC Ernest Rutherford Fellowship (ST/W004119/1) and a University Academic Fellowship from the University of Leeds. C.W. acknowledges financial support from the University of Leeds, the Science and Technology Facilities Council, and UK Research and Innovation (grant numbers ST/T000287/1 and MR/T040726/1). K.S. acknowledges support from the European Research Council under the European Unions Horizon 2020 research and innovation program under grant agreement No. 832428-Origins.Collections
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