Protoplanetary Disks in the Orion Nebula Cluster: Gas-disk Morphologies and Kinematics as Seen with ALMA
Protoplanetary Disks in the Orion Nebula Cluster: Gas-disk Morphologies and Kinematics as Seen with ALMA
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DOI：
10.3847/1538-4357/ab86b7
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
R. D. Boyden;J. Eisner
中科院分区：
文献类型：
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作者：
R. D. Boyden;J. Eisner
我们给出了覆盖猎户座星系团中心1.‘5×1.’5区域的阿塔卡马大毫米阵列CO(3−2)和HCO+(4−3)的观测结果。这些线观测的前所未有的灵敏度(∼0.1mJy BEAM−1)和角分辨率(∼0.“09≈40 Au)使我们能够搜索该地区亚毫米探测尘埃盘的已知位置的气盘探测。我们在GAS中检测到23个盘：17个在CO中(3个−2)，17个在HCO+中(4个−3)，以及11个在两条线上。根据源在ONC中的位置，我们可以看到在发射中、在对暖背景的吸收中、或在发射和吸收中都有线探测。我们对S−-1通道为0.5公里的气体进行了光谱分辨，发现大多数气源的运动学符合开普勒式旋转。我们测量了气盘大小的分布，发现了典型的∼50-200Au半径。因此，与低密度恒星形成区中看到的气盘相比，ONC中的气盘是紧凑的。气体的大小普遍大于尘埃的大小。然而，气体和尘埃的大小并没有很强的相关性。我们发现气体大小与离大质量恒星θ1或C的距离成正相关，这表明ONC中的圆盘受到光致电离的影响。最后，我们使用观测到的气体线的运动学来模拟开普勒式旋转，并推断中央主序恒星的质量。我们的动力学导出的恒星质量与光谱导出的质量不一致，我们讨论了造成这种差异的可能原因。
We present Atacama Large Millimeter Array CO(3 − 2) and HCO+(4 − 3) observations covering the central 1.′5 × 1.′5 region of the Orion Nebula Cluster (ONC). The unprecedented level of sensitivity (∼0.1 mJy beam−1) and angular resolution (∼0.″09 ≈ 40 au) of these line observations enable us to search for gas-disk detections toward the known positions of submillimeter-detected dust disks in this region. We detect 23 disks in gas: 17 in CO(3 − 2), 17 in HCO+(4 − 3), and 11 in both lines. Depending on where the sources are located in the ONC, we see the line detections in emission, in absorption against the warm background, or in both emission and absorption. We spectrally resolve the gas with 0.5 km s−1 channels and find that the kinematics of most sources are consistent with Keplerian rotation. We measure the distribution of gas-disk sizes and find typical radii of ∼50–200 au. As such, gas disks in the ONC are compact in comparison with the gas disks seen in low-density star-forming regions. Gas sizes are universally larger than the dust sizes. However, the gas and dust sizes are not strongly correlated. We find a positive correlation between gas size and distance from the massive star θ1 Ori C, indicating that disks in the ONC are influenced by photoionization. Finally, we use the observed kinematics of the detected gas lines to model Keplerian rotation and infer the masses of the central pre-main-sequence stars. Our dynamically derived stellar masses are not consistent with the spectroscopically derived masses, and we discuss possible reasons for this discrepancy.