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arXiv 1605.01239astro-ph.GA
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恒星的形成和反馈:L1689N中的分子外流-星前核相互作用

Star Formation and Feedback: A Molecular Outflow-Prestellar Core Interaction in L1689N

D. C. Lis, H. A. Wootten, M. Gerin, L. Pagani, E. Roueff, F. F. S van der Tak, C. Vastel, C. M. Walmsley

摘要:

我们提出了赫歇尔,ALMA紧凑阵列(ACA)和加州理工学院亚毫米波天文台(CSO)的观测L1689 N的星前核心,这被认为是与附近的太阳型原恒星IRAS 16293-2422驱动的分子外流相互作用。这个源的特点是在星际介质中看到的一些最高的氘化水平。在NH 2D线速度和宽度的变化,整个核心提供了明确的证据与流出的相互作用,跟踪高速水排放。静止的冷气体,其特征是在核心的NE部分看到窄线宽,而更广泛的,更受干扰的线轮廓被看到在W/SW部分。ACA检测到强N2 D+和ND 3发射,从单盘NH 2D发射的峰值延伸S/SW。ACA的数据还揭示了一个致密的尘埃连续源的存在,其平均大小为~1100 au,中心密度为(1-2)10^7 cm-3,质量为0.2-0.4 Msun。尘埃发射峰相对于N2 D+和ND 3发射以及单碟尘埃连续谱峰向南移位约5”,表明核心的北部静止部分的特征是空间扩展的连续谱发射,这是由干涉仪分辨出来的。我们没有看到明确的证据表明,在这个安静的核心部分,这可能导致第二代恒星形成的碎片,虽然在ACA数据中检测到在该地区的弱尘埃连续源。

英文摘要:

We present Herschel, ALMA Compact Array (ACA), and Caltech Submillimeter Observatory (CSO) observations of the prestellar core in L1689N, which has been suggested to be interacting with a molecular outflow driven by the nearby solar type protostar IRAS 16293-2422. This source is characterized by some of the highest deuteration levels seen in the interstellar medium. The change in the NH2D line velocity and width across the core provides clear evidence of an interaction with the outflow, traced by the high-velocity water emission. Quiescent, cold gas, characterized by narrow line widths is seen in the NE part of the core, while broader, more disturbed line profiles are seen in the W/SW part. Strong N2D+ and ND3 emission is detected with the ACA, extending S/SW from the peak of the single-dish NH2D emission. The ACA data also reveal the presence a compact dust continuum source, with a mean size of ~1100 au, a central density of (1-2) 10^7 cm-3, and a mass of 0.2-0.4 Msun. The dust emission peak is displaced ~5" to the south with respect to the N2D+ and ND3 emission, as well as the single-dish dust continuum peak, suggesting that the northern, quiescent part of the core is characterized by spatially extended continuum emission, which is resolved out by the interferometer. We see no clear evidence of fragmentation in this quiescent part of the core, which could lead to a second generation of star formation, although a weak dust continuum source is detected in this region in the ACA data.

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