Complex organic molecules (COMs) have been identified toward high- and low-mass protostars as well as molecular clouds. Among them, sugar-like and polyol two carbon-bearing molecules such as glycolaldehyde (GA) and ethylene glycol (EG) are of special interest. Recent laboratory experiments have shown that they can efficiently be formed via atom addition reactions between accreting H-atoms and CO molecules or via energetic processes (UV, electrons) on ice analogues containing methanol or formaldehyde. In this study, we report new laboratory experiments on the low-temperature solid state formation of complex organic molecules – the first sugar glyceraldehyde and its saturated derivative glycerol – through VUV photolysis performed at three different temperatures (15, 50, and 90 K) of astrochemically relevant ices composed of water and formaldehyde. We get evidence that the species production depends on the ice temperature during photolysis. The results presented here indicate that a general scheme of aldose and polyol formation is plausible and that heavier COMs than GA and EG could exist in interstellar environments. We propose a general pathway involving radical-formaldehyde reactions as common initiation step for aldose and polyol formation. Future telescope observations may give additional clues on their presence in star-forming regions as observations are currently limited because of the detection thresholds.

中文翻译：

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VUV处理的含甲醛星际冰类似物中的甘油醛和甘油的检测：糖和多元醇的一般形成途径

复杂的有机分子（COMs）已针对高质量和低质量的原恒星以及分子云进行了鉴定。其中，糖类和多元醇两个含碳分子，例如乙醇醛（GA）和乙二醇（EG）引起了特别关注。最近的实验室实验表明，它们可以通过吸附的H原子与CO分子之间的原子加成反应或通过含甲醇或甲醛的冰类似物上的高能过程（紫外线，电子）有效地形成。在这项研究中，我们报告了在三种不同温度（15、50和90 K）下通过VUV光解对复杂有机分子（第一糖甘油醛及其饱和衍生物甘油）进行低温固态形成的新实验室实验。由水和甲醛组成的与天化学相关的冰。我们得到的证据表明，物种的产生取决于光解过程中的冰温。此处给出的结果表明，形成醛糖和多元醇的一般方案是合理的，并且星际环境中可能存在比GA和EG更重的COM。我们提出了涉及自由基-甲醛反应的一般途径，作为醛糖和多元醇形成的常见引发步骤。未来的望远镜观测可能会提供其他线索，说明它们在恒星形成区域中的存在，因为目前的观测由于探测阈值而受到限制。我们提出了涉及自由基-甲醛反应的一般途径，作为醛糖和多元醇形成的常见引发步骤。未来的望远镜观测可能会提供其他线索，说明它们在恒星形成区域中的存在，因为目前的观测由于探测阈值而受到限制。我们提出了涉及自由基-甲醛反应的一般途径，作为醛糖和多元醇形成的常见引发步骤。未来的望远镜观测可能会提供其他线索，说明它们在恒星形成区域中的存在，因为目前的观测由于探测阈值而受到限制。