A specific interstellar aromatic molecule Aromatic molecules such as polycyclic aromatic hydrocarbons (PAHs) are known to exist in the interstellar medium owing to their characteristic infrared emission features. However, the infrared emission only indicates the general class of molecule, and identifying which specific molecular species are present is difficult. McGuire et al. used radio astronomy to detect rotational transitions of benzonitrile emitted from a well-known nearby cloud of interstellar gas (see the Perspective by Joblin and Cernicharo). This molecule may be a precursor to more complex PAHs. The identification of benzonitrile sheds light on the composition of aromatic material within the interstellar medium—material that will eventually be incorporated into new stars and planets. Science, this issue p. 202; see also p. 156 Radio astronomy is used to identify the aromatic molecule benzonitrile in the interstellar medium. Polycyclic aromatic hydrocarbons and polycyclic aromatic nitrogen heterocycles are thought to be widespread throughout the universe, because these classes of molecules are probably responsible for the unidentified infrared bands, a set of emission features seen in numerous Galactic and extragalactic sources. Despite their expected ubiquity, astronomical identification of specific aromatic molecules has proven elusive. We present the discovery of benzonitrile (c-C6H5CN), one of the simplest nitrogen-bearing aromatic molecules, in the interstellar medium. We observed hyperfine-resolved transitions of benzonitrile in emission from the molecular cloud TMC-1. Simple aromatic molecules such as benzonitrile may be precursors for polycyclic aromatic hydrocarbon formation, providing a chemical link to the carriers of the unidentified infrared bands.

中文翻译：

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星际介质中芳香分子苯甲腈（c-C6H5CN）的检测

一种特定的星际芳香分子芳香分子，例如多环芳烃 (PAH)，由于其特有的红外发射特征而存在于星际介质中。然而，红外发射仅指示分子的一般类别，并且难以识别存在哪些特定分子种类。麦奎尔等人。使用射电天文学来探测附近著名的星际气体云发射的苯甲腈的旋转跃迁（参见 Joblin 和 Cernicharo 的观点）。这种分子可能是更复杂的多环芳烃的前体。苄腈的鉴定揭示了星际介质中芳香物质的组成——这些物质最终将被纳入新的恒星和行星。科学，这个问题 p。202; 另见第。156 射电天文学用于识别星际介质中的芳香分子苯甲腈。多环芳烃和多环芳族氮杂环被认为在整个宇宙中广泛存在，因为这些类别的分子可能是不明红外波段的原因，这是在众多银河和河外来源中看到的一组发射特征。尽管它们普遍存在，但已证明对特定芳香分子的天文鉴定难以捉摸。我们在星际介质中发现了苄腈 (c-C6H5CN)，这是最简单的含氮芳香分子之一。我们在分子云 TMC-1 的发射中观察到了苄腈的超精细分辨跃迁。