猎户座大质量核动力学状态的二分法
Dichotomy in the Dynamical Status of Massive Cores in Orion
摘要：
为了研究高质量核心的演化，我们在猎户座分子云的大样本无星核心中寻找坍缩运动的证据。我们使用加州理工学院亚毫米波天文台的望远镜，获得光谱的光学薄（\H 13 CO+）和光学厚（\HCO +）的高密度示踪分子在27个核心与质量$>$ 1 \Ms。在光学粗线相对于光学细线的线轮廓中看到的红色和蓝色不对称性表明这些芯中的2/3不是静态的。我们检测到的证据，在9个核心和10个核心向外运动的下落（向内运动），这表明在这个样本中的非静态核心的运动状态的二分法。我们的研究结果提供了一个重要的观测约束崩溃（向内运动）与非崩溃（再膨胀）的核心与模型模拟比较的分数。
英文摘要：
To study the evolution of high mass cores, we have searched for evidence of collapse motions in a large sample of starless cores in the Orion molecular cloud. We used the Caltech Submillimeter Observatory telescope to obtain spectra of the optically thin (\H13CO+) and optically thick (\HCO+) high density tracer molecules in 27 cores with masses $>$ 1 \Ms. The red- and blue-asymmetries seen in the line profiles of the optically thick line with respect to the optically thin line indicate that 2/3 of these cores are not static. We detect evidence for infall (inward motions) in 9 cores and outward motions for 10 cores, suggesting a dichotomy in the kinematic state of the non-static cores in this sample. Our results provide an important observational constraint on the fraction of collapsing (inward motions) versus non-collapsing (re-expanding) cores for comparison with model simulations.
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