Warm CO Gas Generated by Possible Turbulent Shocks in a Low-mass Star-forming Dense Core in Taurus
Warm CO Gas Generated by Possible Turbulent Shocks in a Low-mass Star-forming Dense Core in Taurus
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DOI：
10.3847/1538-4357/aac898
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发表时间：
2018-04
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通讯作者：
K. Tokuda;T. Onishi;K. Saigo;Tomoaki Matsumoto;T. Inoue;S. Inutsuka;Y. Fukui;M. Machida;K. Tomida;T. Hosokawa;A. Kawamura;K. Tachihara
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作者：
K. Tokuda;T. Onishi;K. Saigo;Tomoaki Matsumoto;T. Inoue;S. Inutsuka;Y. Fukui;M. Machida;K. Tomida;T. Hosokawa;A. Kawamura;K. Tachihara
我们报告了阿尔马周期3观测的CO同位素对致密的核心，MC 27/L1521 F在金牛座，这被认为是在早期阶段的多星星形成的湍流环境。虽然这个核心的大部分高密度部分被认为是冷至1000 K，但在12 CO（J = 3-2）中的高角分辨率（1020 Au）观测揭示了复杂的温暖（>15-60 K）的星系/星系结构，其大小从几十个天文单位到1000 Au。13 CO和C18 O的干涉观测表明，与先前确定的原恒星和凝聚体相关的弧状形态的致密部分从核心的系统速度略有红移。我们认为，温暖的CO云可能是冲击加热引起的不同的密度/速度分量之间的相互作用，起源于在核心的湍流运动的后果。然而，这种小尺度和快速湍流运动并不对应于线宽-尺寸关系的简单扩展（即，拉尔森定律），因此实际的起源仍有待研究。高角分辨率的CO观测预计是必不可少的，在检测小规模的湍流运动在致密的核心，并调查其中的原恒星形成。
We report ALMA Cycle 3 observations in CO isotopes toward a dense core, MC27/L1521F in Taurus, which is considered to be at an early stage of multiple star formation in a turbulent environment. Although most of the high-density parts of this core are considered to be as cold as ∼10 K, high-angular resolution (∼20 au) observations in 12CO (J = 3–2) revealed complex warm (>15–60 K) filamentary/clumpy structures with the sizes from a few tens of astronomical units to ∼1000 au. The interferometric observations of 13CO and C18O show that the densest part with arc-like morphologies associated with the previously identified protostar and condensations are slightly redshifted from the systemic velocity of the core. We suggest that the warm CO clouds may be consequences of shock heating induced by interactions among the different density/velocity components that originated from the turbulent motions in the core. However, such a small-scale and fast turbulent motion does not correspond to a simple extension of the line–width–size relation (i.e., Larson's law), and thus the actual origin remains to be studied. The high-angular resolution CO observations are expected to be essential in detecting small-scale turbulent motions in dense cores and to investigate protostar formation therein.