Molecules with ALMA at Planet-forming Scales (MAPS): A Circumplanetary Disk Candidate in Molecular-line Emission in the AS 209 Disk

Bae, Jaehan and Teague, Richard and Andrews, Sean M. and Benisty, Myriam and Facchini, Stefano and Galloway-Sprietsma, Maria and Loomis, Ryan A. and Aikawa, Yuri and Alarcón, Felipe and Bergin, Edwin and Bergner, Jennifer B. and Booth, Alice S. and Cataldi, Gianni and Cleeves, L. Ilsedore and Czekala, Ian and Guzmán, Viviana V. and Huang, Jane and Ilee, John D. and Kurtovic, Nicolas T. and Law, Charles J. and Gal, Romane Le and Liu, Yao and Long, Feng and Ménard, François and Öberg, Karin I. and Pérez, Laura M. and Qi, Chunhua and Schwarz, Kamber R. and Sierra, Anibal and Walsh, Catherine and Wilner, David J. and Zhang, Ke (2022) Molecules with ALMA at Planet-forming Scales (MAPS): A Circumplanetary Disk Candidate in Molecular-line Emission in the AS 209 Disk. The Astrophysical Journal Letters, 934 (2). L20. ISSN 2041-8205

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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 1farcs4 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 MJup ≃ 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.

Item Type: Article
Subjects: Archive Paper Guardians > Physics and Astronomy
Depositing User: Unnamed user with email support@archive.paperguardians.com
Date Deposited: 25 Apr 2023 09:22
Last Modified: 30 Mar 2024 03:53
URI: http://archives.articleproms.com/id/eprint/760

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