A Micro-Molecular Bipolar Outflow from HL Tauri
A Micro-Molecular Bipolar Outflow from HL Tauri
复制标题
HL Tauri 的小分子双极流出
DOI：
10.1086/524138
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Christopher Davis
中科院分区：
文献类型：
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作者：
M. Takami;T. Beck;T. Pyo;P. Mcgregor;Christopher Davis
我们介绍了在双子座-北8米天文台使用近红外积分场光谱仪（NIFS）观测到的向HL Tau内部流出的详细几何和运动学。我们分析了H2 2.122 μm发射和[Fe II] 1.644 μm线发射以及在<0.2”分辨率下观察到的相邻连续体。H2的发射表现为(1)恒星东北方向的气泡状几何形状，如前一篇论文中简要报道的那样；(2)在西南逆流中微弱的发射，通过仔细的分析已经揭示出来。恒星两侧的辐射显示出距离恒星1.0英寸的弧线，表现出两极对称。东北和西南气流的不同亮度和形态归因于后者被扁平的包层和星周圆盘吸收和遮挡。H2发射表现出与[Fe II]发射中的准直射流明显不同的形态。一些特征的位置与散射连续体一致，表明这些特征与尘埃包层中的空洞有关。这种性质与毫米级CO流出物相似，尽管我们图像中H2流出物的空间尺度（~150 AU）明显小于毫米级CO流出物，后者通常超过1000-10000 AU尺度。H2和[Fe II]发射的位置-速度图没有显示出这些流动之间的运动相互作用的任何证据。上述所有结果都支持这样一种假设，即射流被一种看不见的广角风所包围，这种风与周围的气体相互作用，产生了双极空腔和激波H2发射。
We present detailed geometry and kinematics of the inner outflow toward HL Tau observed using Near Infrared Integral Field Spectrograph (NIFS) at the Gemini-North 8 m Observatory. We analyzed H2 2.122 μm emission and [Fe II] 1.644 μm line emission as well as the adjacent continuum observed at a <0.2'' resolution. The H2 emission shows (1) a bubble-like geometry to the northeast of the star, as briefly reported in the previous paper, and (2) faint emission in the southwest counterflow, which has been revealed through careful analysis. The emission on both sides of the star shows an arc 1.0'' away from the star, exhibiting a bipolar symmetry. Different brightnesses and morphologies in the northeast and southwest flows are attributed to absorption and obscuration of the latter by a flattened envelope and a circumstellar disk. The H2 emission shows a remarkably different morphology from the collimated jet seen in [Fe II] emission. The positions of some features coincide with scattering continuum, indicating that these are associated with cavities in the dusty envelope. Such properties are similar to millimeter CO outflows, although the spatial scale of the H2 outflow in our image (~150 AU) is strikingly smaller than the millimeter outflows, which often extend over 1000-10000 AU scales. The position-velocity diagrams of the H2 and [Fe II] emission do not show any evidence for kinematic interaction between these flows. All results described above support the scenario that the jet is surrounded by an unseen wide-angled wind, which interacts with the ambient gas and produces the bipolar cavity and shocked H2 emission.