We present high spectral resolution optical observations of comet 21P/Giacobini–Zinner from six nights in 2018. The observations were obtained with the Tull Coud Spectrograph on the 2.7 m Harlan J. Smith Telescope of the McDonald Observatory. This comet’s spectrum shows strong depletions in C₂, C₃, CH, and NH₂ relative to CN. We explore what it means for a comet to be depleted and show that all of the species are present in the spectrum at similar relative line intensities within a a molecular band compared with a typical comet. The depletions represent a much lower abundance of the species studied.

中文翻译：

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成为“耗尽”彗星意味着什么？麦当劳天文台对原型贫乏彗星21P / Giacobini-Zinner的高光谱分辨率观测

我们将在2018年的六个晚上提供21P / Giacobini-Zinner彗星的高光谱分辨率光学观测结果。这些观测结果是通过麦当劳天文台2.7 m的哈兰·史密斯望远镜的Tull Coud光谱仪获得的。该彗星的光谱显示相对于CN而言，C ₂，C ₃，CH和NH _2的强烈消耗。我们探索了彗星被耗尽的含义，并表明与典型的彗星相比，所有物种在一个分子带内以相似的相对线强度出现在光谱中。耗竭表明所研究物种的丰度要低得多。