Nucleobases are of significant importance to all known organisms, may be an important building block of life, and could be important biosignatures of current or past life. Given their potential significance to the field of astrobiology, it is important to understand the survival of these molecules when subjected to ionizing radiation as is present in a range of extraterrestrial environments. In this work, we present data on the kinetics of the radiolytic destruction of pure thymine and water + thymine ice mixtures at temperatures from 13 to 150 K. Rate constants were measured using in situ infrared spectroscopy, and radiolytic half-lives for thymine were computed for different planetary and interstellar environments. Our results demonstrate that the survival of thymine decreases as the dilution of thymine in water increases. Additionally, we find that thymine survival increases with ice temperature and that this decrease may be related to structure of the ice matrix.

中文翻译：

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胸腺嘧啶在固体水中的辐射稳定性。

核糖核酸酶对所有已知生物都至关重要，可能是生命的重要组成部分，并且可能是当前或过去生命的重要生物特征。考虑到它们对天文生物学领域的潜在重要性，重要的是要了解这些分子在电离辐射下的生存能力，这些辐射存在于一系列地球外环境中。在这项工作中，我们提供了在13至150 K的温度下对纯胸腺嘧啶和水+胸腺嘧啶冰混合物进行放射分解破坏动力学的数据。使用原位测量速率常数红外光谱和胸腺嘧啶的辐射半衰期是针对不同的行星和星际环境计算的。我们的结果表明，胸腺嘧啶的存活率随胸腺嘧啶在水中的稀释度增加而降低。此外，我们发现胸腺嘧啶的存活率随冰温度的升高而增加，而这种降低可能与冰基质的结构有关。