New Insights into the Chemical Composition of Five Oort Cloud Comets after Re-analysis of Their Infrared Spectra
New Insights into the Chemical Composition of Five Oort Cloud Comets after Re-analysis of Their Infrared Spectra
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重新分析五颗奥尔特云彗星的红外光谱后其化学成分的新见解
DOI：
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发表时间：
2020
影响因子：
5.3
通讯作者：
L. Paganini
中科院分区：
文献类型：
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作者：
M. Lippi;G. Villanueva;M. Mumma;M. Camarca;S. Faggi;L. Paganini
我们提出了1999年至2012年期间在凯克天文台使用近红外中阶梯光栅光谱仪（NIRSPEC）观测的五颗奥尔特云彗星（C/1999 S4（LINEAR），C/2001 A2（LINEAR），C/2007 W1（Boattini），C/2012 F6（Lemmon）和C/2012 S1（ISON））中主要分子物种的修订结果。对这些数据的重新评价表明，一些数据集的结果有所改善，特别是在2011年以来采用的新的和经修订的荧光模型和地面检索方法出现之前观测和分析的彗星。我们观察到显着改善所产生的旋转温度和生产率的所有物种，并在混合比例的次要物种（相对于水）。重新分析还使我们能够量化以前没有分析过的物种，主要是由于缺乏分子模型（例如，氨和甲醛）。然而，我们注意到，自2010年以来观测（和/或分析）的彗星的这些修订值的改善不太显著。
We present revised results for the main molecular species in five Oort Cloud comets observed with near-infrared echelle grating spectrometer (NIRSPEC) at the Keck Observatory between 1999 and 2012 (C/1999 S4 (LINEAR), C/2001 A2 (LINEAR), C/2007 W1 (Boattini), C/2012 F6 (Lemmon), and C/2012 S1 (ISON)). The re-evaluation of these data shows the improvement of results in some of the data sets, in particular for comets observed and analyzed before the advent of new and revised fluorescence models and terrestrial retrieval methods introduced since 2011. We observe significant improvements in the resulting rotational temperatures and the production rates for all species, and in mixing ratios of minor species (relative to water). The re-analysis also allowed us to quantify species not analyzed previously, mostly due to the lack of molecular models (e.g., ammonia and formaldehyde). We note, however, that the improvement of these revised values is less substantial for comets observed (and/or analyzed) since 2010.