UvA-DARE ( Digital Academic Repository ) Revisiting the solid HDO / H 2 O abundances
UvA-DARE ( Digital Academic Repository ) Revisiting the solid HDO / H 2 O abundances
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UvA-DARE（数字学术知识库）重新审视固体 HDO / H 2 O 丰度
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通讯作者：
E. Dishoeck
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作者：
E. Dartois;W. Thi;T. Geballe;L. d’Hendecourt;E. Dishoeck
我们利用独立的VLT-ISAAC和UKIRT-CGS4光谱观测，回顾了已有报道的在大质量年轻原恒星Gl 2136和W33 A分子云环境中存在的冰幔中HDO的探测和上限。我们还获得了RAFGL 7009在HDO吸收波长附近的VLT和UKIRT光谱，并重新分析了NGC 7538 IRS9、猎户座bn和S140的ISO-SWS光谱数据。我们证明之前报道的W33 A和NGC 7538 IRS9中HDO的检测是不正确的。我们提出了一项深入的分析，表明除了灵敏度限制外，当存在固体甲醇（一种常见的颗粒地幔成分）的特征时，在无定形冰地幔中检测低水平的HDO是困难的。我们讨论了NGC 7538 IRS9在这个波长范围内的ISO数据中出现的具体问题。利用VLT-ISAAC观测，我们还研究了中间质量恒星IRAS 05329-0728和IRAS 08448-4343的HDO/H2O比值。我们得出的水冰中D/H比的上限在不同来源的HDO/H2O < 1%到0.2%之间，我们将这些上限与其他环境中得出的值进行了比较。
We revisit the reported detection and upper limits on HDO in ice mantles present in the molecular cloud environments of the massive young protostars Gl 2136 and W33 A, using independent VLT-ISAAC and UKIRT-CGS4 spectroscopic observations. We also present VLT and UKIRT spectra of RAFGL 7009 near the HDO absorption wavelength and reanalyze the ISO-SWS spectral data for NGC 7538 IRS9, Orion-BN and S140. We demonstrate that the previously reported detections of HDO in W33 A and NGC 7538 IRS9 are incorrect. We present an in-depth analysis that shows that, besides the sensitivity limits, detection of low levels of HDO is difficult in amorphous ice mantles when features from solid methanol, a common grain mantle constituent, are present. We discuss the specific problems arising in the ISO data in this wavelength range for NGC 7538 IRS9. Using VLT-ISAAC observations, we also investigate the HDO/H2O ratio toward the intermediate mass stars IRAS 05329–0728 and IRAS 08448–4343. Our derived upper limits for the D/H ratio in water ice range from HDO/H2O < 1% to 0.2% in the different sources, and we discuss these limits in comparison with values derived in other environments.