Dust and gas emission in the prototypical hot core G29.96-0.02 at sub-arcsecond resolution
Dust and gas emission in the prototypical hot core G29.96-0.02 at sub-arcsecond resolution
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原型热核心 G29.96-0.02 中亚弧秒分辨率的灰尘和气体排放
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
S. Leurini
中科院分区：
文献类型：
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作者：
H. Beuther;Q. Zhang;E. Bergin;Sridharan T. K.;T. Hunter;S. Leurini
上下文。热分子核是大质量恒星形成的早期表现，其中分子气体被加热到100 - 100 K的温度，并经历复杂的化学反应。目标。人们想要更好地理解这个早期进化阶段的物理和化学过程。方法。我们选择了位于相关超紧凑Hii区头部的典型热分子核G29.96−0.02。利用亚毫米波阵列（SMA）以亚弧秒的空间分辨率获得了862µm的亚毫米连续谱和谱线数据。结果。SMA将热分子核分解成6个亚毫米连续源，迄今为止实现的最佳空间分辨率为0.36°×0.25°（~ 1800 AU）。其中四个位于7800 (AU) 2内，组成了一个原四边形系统，估计原恒星密度为1.4×10 5颗原恒星/ pc3。过量的~ 80条光谱线使我们能够研究分子流出，核心运动学，该区域的温度结构以及化学效应。所得的热芯温度约为300k。我们发现了有趣的化学空间分异，例如，c34s向热岩心方向缺乏，而在UCHii/热岩心界面处增强，这可能与颗粒的温敏解吸和随后的气相化学有关。SiO（8−7）发射勾勒出可能从这个热核区域发出的两种分子外流。大多数其他分子的辐射峰集中在热核上，不受任何单个亚毫米峰的支配。讨论了可能的原因。与主亚毫米连续源有关的几条光谱线显示出垂直于大规模流出的速度梯度。由于这个速度结构由三个中心原恒星源组成，所以它不是开普勒盘。虽然数据与可能旋转和/或坍缩的气体核心一致，但我们不能排除流出和/或附近膨胀的UCHii区域可能是这种速度模式的另一种原因。
Context. Hot molecular cores are an early manifestation of massive star formation where the molecular gas is heated to temperatures >100 K undergoing a complex chemistry. Aims. One wants to better understand the physical and chemical processes in this early evolutionary stage. Methods. We selected the prototypical hot molecular core G29.96−0.02 being located at the head of the associated ultracompact Hii region. The 862 µm submm continuum and spectral line data were obtained with the Submillimeter Array (SMA) at sub-arcsecond spatial resolution. Results. The SMA resolved the hot molecular core into six submm continuum sources with the finest spatial resolution of 0.36 �� ×0.25 �� (∼1800 AU) achieved so far. Four of them located within 7800 (AU) 2 comprise a proto-Trapezium system with estimated protostellar densities of 1.4×10 5 protostars/pc 3 . The plethora of ∼80 spectral lines allows us to study the molecular outflow(s), the core kinematics, the temperature structure of the region as well as chemical effects. The derived hot core temperatures are of the order 300 K. We find interesting chemical spatial differentiations, e.g., C 34 S is deficient toward the hot core and is enhanced at the UCHii/ hot core interface, which may be explained by temperature sensitive desorption from grains and following gas phase chemistry. The SiO(8−7) emission outlines likely two molecular outflows emanating from this hot core region. Emission from most other molecules peaks centrally on the hot core and is not dominated by any individual submm peak. Potential reasons for that are discussed. A few spectral lines that are associated with the main submm continuum source, show a velocity gradient perpendicular to the large-scale outflow. Since this velocity structure comprises three of the central protostellar sources, this is not a Keplerian disk. While the data are consistent with a gas core that may rotate and/or collapse, we cannot exclude the outflow(s) and/or nearby expanding UCHii region as possible alternative causes of this velocity pattern.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell