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

DOI：

10.3847/2041-8213/ac7fa3

发表时间：

2022-07

期刊：

The Astrophysical Journal Letters

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

J. Bae;R. Teague;S. Andrews;M. Benisty;S. Facchini;Maria Galloway-Sprietsma;R. Loomis;Y. Aikawa;Felipe Alarcón;E. Bergin;J. Bergner;A. Booth;G. Cataldi;L. Cleeves;I. Czekala;V. Guzmán;Jane Huang;J. Ilee;N. Kurtovic;C. Law;R. L. Gal;Yao Liu;F. Long;F. Ménard;K. Oberg;L. Pérez;C. Qi;K. Schwarz;A. Sierra;Catherine Walsh;D. Wilner;Kecheng Zhang

我们报告发现，在金牛座 T 星 AS 209 的星周盘中发现了一个候选环行星盘（CPD），其径向距离约为 200 天文单位（在天空中与恒星的距离为 1.″4，方位角为 161°），通过 13CO J = 2−1 发射进行隔离。这是通过气体发射进行 CPD 检测的第一个实例，能够追踪 CPD 的整体质量。 CPD 在空间上未解析为 117 × 82 mas 光束，并在 13CO 中表现为点源，表明其直径为 ≲14 au。 CPD 嵌入先前使用 12CO 和近红外散射光观测识别的星周盘的环形间隙内，并且与 12CO 中的局部速度扰动相关。这些特征的巧合表明它们有一个共同的起源：一颗嵌入的巨行星。我们使用 13CO 强度来约束 CPD 气体温度和质量。我们发现CPD温度≳35 K，高于CPD径向位置处的星周盘温度22 K，这表明一定存在位于CPD的热源。采用标准 13CO 丰度时，CPD 气体质量为 ≳0.095 M Jup ≃ 30 M ⊕。根据 CPD 位置未检测到毫米连续发射（3σ 通量密度 ≲26.4 μJy），我们推断 CPD 尘埃质量为 ≲0.027 M ⊕ ≃ 2.2 月球质量，表明尘埃与气体的质量比较低，为 ≲9 × 10−4。我们在引力不稳定和卵石吸积的框架下讨论了宽轨道上 CPD 巨行星的形成机制。

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.

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

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