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arXiv 1305.2247astro-ph.GA
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来自Herschel/HIFI的Orion KL中H2O和HDO的丰度

The abundance of H2O and HDO in Orion KL from Herschel/HIFI

Justin L. Neill, Shiya Wang, Edwin A. Bergin, Nathan R. Crockett, Cécile Favre, René Plume, Gary J. Melnick

摘要:

使用宽带,高光谱分辨率的调查对猎户座KL收购与赫歇尔/HIFI的HEXOS关键程序的一部分,我们得出的H $_2$ O和HDO的丰度在不同的空间/速度分量与这个大规模的恒星形成区域:热核心,致密岭,高原。在分析中使用了总共20个H $_2$ $^{18}$ O跃迁,14个H $_2$ $^{17}$ O跃迁,37个HD $^{16}$ O跃迁,6个HD $^{18}$ O跃迁和6个D $_2$ O跃迁,从基态跃迁跨越到上态能量超过1200 K。低激发线检测到多个组件,但最高的激发线($E_u >$ 500 K)被很好地模拟为从一个小的($\sim 2"$)丛发射具有高丰度的H $_2$ O($χ= 6.5 \times 10^{-4}$相对于H $_2$)和HDO/H $_2$ O比为0.003。使用高空间分辨率($1.5" \times 1.1"$)图像的两个过渡的HDO测量ALMA作为其科学验证阶段的一部分,我们确定该组件位于附近,但不直接重合,已知的连续源在热核心区域。在致密海脊和高原部分也发现了显著的HDO/H $_2$ O分馏。流出的气体,观察到的发射和吸收组件,具有较低的HDO/H $_2$ O比在猎户座KL,我们建议的紧凑型组件可能是由于修改气相冲击化学。

英文摘要:

Using a broadband, high spectral resolution survey toward Orion KL acquired with Herschel/HIFI as part of the HEXOS key program, we derive the abundances of H$_2$O and HDO in the different spatial/velocity components associated with this massive star-forming region: the Hot Core, Compact Ridge, and Plateau. A total of 20 transitions of H$_2$$^{18}$O, 14 of H$_2$$^{17}$O, 37 of HD$^{16}$O, 6 of HD$^{18}$O, and 6 of D$_2$O are used in the analysis, spanning from ground state transitions to over 1200 K in upper-state energy. Low-excitation lines are detected in multiple components, but the highest-excitation lines ($E_u >$ 500 K) are well modeled as emitting from a small ($\sim 2"$) clump with a high abundance of H$_2$O ($χ= 6.5 \times 10^{-4}$ relative to H$_2$) and a HDO/H$_2$O ratio of 0.003. Using high spatial resolution ($1.5" \times 1.1"$) images of two transitions of HDO measured by ALMA as part of its science verification phase, we identify this component as located near, but not directly coincident with, known continuum sources in the Hot Core region. Significant HDO/H$_2$O fractionation is also seen in the Compact Ridge and Plateau components. The outflowing gas, observed with both emission and absorption components, has a lower HDO/H$_2$O ratio than the compact components in Orion KL, which we propose could be due to modification by gas-phase shock chemistry.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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