Recent simulations have indicated that vinyl cyanide is the best candidate molecule for the formation of cell membranes/vesicle structures in Titan’s hydrocarbon-rich lakes and seas. Although the existence of vinyl cyanide (C2H3CN) on Titan was previously inferred using Cassini mass spectrometry, a definitive detection has been lacking until now. We report the first spectroscopic detection of vinyl cyanide in Titan’s atmosphere, obtained using archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), collected from February to May 2014. We detect the three strongest rotational lines of C2H3CN in the frequency range of 230 to 232 GHz, each with >4σ confidence. Radiative transfer modeling suggests that most of the C2H3CN emission originates at altitudes of ≳200 km, in agreement with recent photochemical models. The vertical column densities implied by our best-fitting models lie in the range of 3.7 × 1013 to 1.4 × 1014 cm−2. The corresponding production rate of vinyl cyanide and its saturation mole fraction imply the availability of sufficient dissolved material to form ~107 cell membranes/cm3 in Titan’s sea Ligeia Mare.
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机译:最近的模拟表明,氰化乙烯基化合物是土卫六富含烃的湖泊和海洋中形成细胞膜/囊泡结构的最佳候选分子。尽管先前曾使用卡西尼质谱仪推断出泰坦上存在氰化乙烯(C2H3CN),但迄今为止仍缺乏确定的检测方法。我们报告了首次使用泰坦大气中氰化乙烯的光谱检测方法,该方法是使用2014年2月至2014年5月收集的阿塔卡马大型毫米/亚毫米阵列(ALMA)的档案数据获得的。我们检测到C2H3CN的三个最强旋转线在230至232 GHz,每个具有>4σ置信度。辐射转移模型表明,与最近的光化学模型一致,大多数C2H3CN排放起源于at200 km的高度。我们的最佳拟合模型隐含的垂直列密度在3.7×10 13 sup>到1.4×10 14 sup> cm −2 sup>的范围内。相应的乙烯基氰化物的生产率及其饱和摩尔分数意味着在泰坦海的Ligeia Mare中有足够的溶解物质来形成〜10 7 sup>细胞膜/ cm 3 sup>。
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