Rotating Filament in Orion B: Do Cores Inherit Their Angular Momentum from Their Parent Filament?
Rotating Filament in Orion B: Do Cores Inherit Their Angular Momentum from Their Parent Filament?
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DOI：
10.3847/1538-4357/abd034
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
Cheng-Han 翰 Hsieh 承;H. Arce;D. Mardones;Shuo Kong;A. Plunkett
中科院分区：
文献类型：
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作者：
Cheng-Han 翰 Hsieh 承;H. Arce;D. Mardones;Shuo Kong;A. Plunkett
角动量是控制星星形成的最重要的物理量之一。核心的初始角动量可能是造成其碎裂的原因，并且会影响原行星盘的大小。为了理解核心如何获得它们的初始角动量，重要的是研究它们形成的细丝的角动量。虽然对暗条旋转的理论研究已经进行了探索，但对恒星形成中暗条的特定角动量的观测测量很少。我们提出了猎户座B中LBS 23（HH 24-HH 26）区域的高分辨率N2 D+阿尔马观测，它提供了恒星形成灯丝中特定角动量的最可靠测量之一。我们发现总的比角动量（4 × 1020 cm 2 s−1），比角动量与半径的关系（j（r）<$r 1.83），以及转动能与引力能的比值（βrot <$0.04）与在其他恒星形成区域中观测到的尺寸与我们的细丝宽度（<$0.04 pc）相似的旋转核心相当。我们的灯丝角动量分布与从环境湍流获得的旋转和模拟结果一致，模拟结果表明，由于湍流产生的非线性扰动的多尺度增长，核心和它们的宿主灯丝同时发展。
Angular momentum is one of the most important physical quantities that governs star formation. The initial angular momentum of a core may be responsible for its fragmentation, and can have an influence on the size of the protoplanetary disk. To understand how cores obtain their initial angular momentum, it is important to study the angular momentum of filaments where they form. While theoretical studies on filament rotation have been explored, there exist very few observational measurements of the specific angular momentum in star-forming filaments. We present high-resolution N2D+ ALMA observations of the LBS 23 (HH24-HH26) region in Orion B, which provide one of the most reliable measurements of the specific angular momentum in a star-forming filament. We find the total specific angular momentum (4 × 1020 cm2 s−1), the dependence of the specific angular momentum with radius (j(r) ∝ r1.83), and the ratio of rotational energy to gravitational energy (βrot ∼ 0.04) comparable to those observed in rotating cores with sizes similar to our filament width (∼0.04 pc) in other star-forming regions. Our filament angular momentum profile is consistent with rotation acquired from ambient turbulence and with simulations that show cores and their host filaments develop simultaneously due to multi-scale growth of nonlinear perturbation generated by turbulence.