The Chemistry of Phosphorus-bearing Molecules under Energetic Phenomena
The Chemistry of Phosphorus-bearing Molecules under Energetic Phenomena
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DOI：
10.3847/1538-4357/aacdf2
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
I. Jímenez-Serra;S. Viti;D. Quénard;J. Holdship
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文献类型：
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作者：
I. Jímenez-Serra;S. Viti;D. Quénard;J. Holdship
几十年来，星际介质中含磷分子的探测仅限于高质量恒星形成区域（例如，SgrB 2和猎户座KL）和演化恒星的拱星包络。然而，最近的高灵敏度观测显示，像PN和PO这样的分子不仅存在于冷的大质量核心和PO/PN比值≥1的低质量恒星形成区，而且还存在于银河系中心的巨型分子云，这些分子云暴露于高能现象，如强烈的紫外辐射场，冲击波和宇宙射线。在本文中，我们对不同天体物理环境中含磷分子的化学进行了全面的研究，这些环境涵盖了一系列物理条件（冷分子暗云，暖云和热核心/热科里诺），并暴露于不同的物理过程和能量现象（原恒星加热，冲击波，强烈的紫外线辐射和宇宙射线）。我们展示了测量的PO/PN比（或者≥1，例如，热分子核，或≤1，如在UV强照射环境中）可以提供对源的物理条件和能量处理的约束。我们认为，P + OH → PO + H反应可能是激波中生成PO的有效途径。我们的建模提供了一个模板，研究P-轴承物种的可探测性，不仅在我们自己的银河系的地区，而且在河外来源。
For decades, the detection of phosphorus-bearing molecules in the interstellar medium was restricted to high-mass star-forming regions (e.g., SgrB2 and Orion KL) and the circumstellar envelopes of evolved stars. However, recent higher-sensitivity observations have revealed that molecules such as PN and PO are present not only toward cold massive cores and low-mass star-forming regions with PO/PN ratios ≥1 but also toward the giant molecular clouds in the Galactic center known to be exposed to highly energetic phenomena such as intense UV radiation fields, shock waves, and cosmic rays. In this paper, we carry out a comprehensive study of the chemistry of phosphorus-bearing molecules across different astrophysical environments that cover a range of physical conditions (cold molecular dark clouds, warm clouds, and hot cores/hot corinos) and are exposed to different physical processes and energetic phenomena (proto-stellar heating, shock waves, intense UV radiation, and cosmic rays). We show how the measured PO/PN ratio (either ≥1, as in, e.g., hot molecular cores, or ≤1, as in UV strongly illuminated environments) can provide constraints on the physical conditions and energetic processing of the source. We propose that the reaction P + OH → PO + H, not included in previous works, could be an efficient gas-phase PO formation route in shocks. Our modeling provides a template with which to study the detectability of P-bearing species not only in regions in our own Galaxy but also in extragalactic sources.