Models for Dense Molecular Cloud Cores
Models for Dense Molecular Cloud Cores
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DOI：
10.1086/304764
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发表时间：
1997-07
期刊：
影响因子：
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通讯作者：
S. Doty;D. Neufeld
中科院分区：
文献类型：
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作者：
S. Doty;D. Neufeld
我们提出了一个详细的理论模型的热平衡，化学和辐射传输内的静态致密的分子云核心，包含一个中央原恒星。在这样的核心的内部，我们预计的灰尘和气体的温度耦合良好，而在外部区域CO旋转排放占主导地位的气体冷却和预测的气体温度位于显着低于尘埃温度。大的空间变化的气体温度预计会影响气相化学显着，特别是，预测的水丰度变化超过1000倍的云核内包含发光的原恒星。根据我们对云核热力学和化学结构的预测，我们建立了自洽辐射传输模型，计算了12 CO，13 CO，C18 O，ortho-和para-H162 O，ortho-和para-H182 O，和O I跃迁的谱线强度和谱线轮廓。我们进行了一个一般的参数研究，以确定依赖的模型预测的参数假设的来源。我们希望许多远红外和亚毫米旋转过渡的水可以检测到无论是在发射或吸收与使用红外空间天文台（ISO）和亚毫米波天文卫星。静止的，辐射加热的热核预计将在183 GHz 313-220水线显示低增益脉泽发射，例如已经观察到对几个热核区域使用地面望远镜。我们预言了63 μm附近氧原子3 P1 - 3 P2精细结构跃迁对许多源的连续谱都有强吸收。我们的模型也可以成功地解释最近ISO观测到的吸收在振转转换的水对源AFGL 2591。
We present a detailed theoretical model for the thermal balance, chemistry, and radiative transfer within quiescent dense molecular cloud cores that contain a central protostar. In the interior of such cores, we expect the dust and gas temperatures to be well coupled, while in the outer regions CO rotational emissions dominate the gas cooling and the predicted gas temperature lies significantly below the dust temperature. Large spatial variations in the gas temperature are expected to affect the gas phase chemistry dramatically; in particular, the predicted water abundance varies by more than a factor of 1000 within cloud cores that contain luminous protostars. Based upon our predictions for the thermal and chemical structure of cloud cores, we have constructed self-consistent radiative transfer models to compute the line strengths and line profiles for transitions of 12CO,13CO, C18O, ortho- and para-H162O, ortho- and para-H182O, and O I. We carried out a general parameter study to determine the dependence of the model predictions upon the parameters assumed for the source. We expect many of the far-infrared and submillimeter rotational transitions of water to be detectable either in emission or absorption with the use of the Infrared Space Observatory (ISO) and the Submillimeter Wave Astronomy Satellite. Quiescent, radiatively heated hot cores are expected to show low-gain maser emission in the 183 GHz 313-220 water line, such as has been observed toward several hot core regions using ground-based telescopes. We predict the 3P1-3P2 fine-structure transition of atomic oxygen near 63 μm to be in strong absorption against the continuum for many sources. Our model can also account successfully for recent ISO observations of absorption in rovibrational transitions of water toward the source AFGL 2591.