Comets: Role and importance to exobiology
Comets: Role and importance to exobiology
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彗星：对外太空生物学的作用和重要性
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
A. Delsemme
中科院分区：
文献类型：
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作者：
A. Delsemme
有机化合物从星际空间转移到原行星盘的边缘，它们被吸积成彗星状物体，而彗星状物体通过轨道扩散进入太阳系内部，这为外太空生物学的核心问题提供了新的视角。这表明存在一种宇宙机制，它在任何地方都起作用，可以为无处不在的岩石行星提供益生元化合物，在宇宙的许多地方寻找适宜的环境来孕育生命。在彗星核化学的标题下，涵盖了以下主题：核的径向均匀性；尘冰比；尘粒的性质；彗星尘埃的起源；挥发分的性质；哈雷彗星CO的分布；粉尘对挥发分的贡献；哈雷彗星元素资产负债表；挥发分的定量分子分析；还有同位素比。在类地行星上碳的外源起源的标题下，包括以下主题：高温阶段的证据；从星子到行星；饰面：由挥发性和有机材料制成的饰面；还有彗星的贡献。
The transfer of organic compounds from interstellar space to the outskirts of a protoplanetary disk, their accretion into cometary objects, and the transport of the latter into the inner solar system by orbital diffusion throw a new light on the central problem of exobiology. It suggests the existence of a cosmic mechanism, working everywhere, that can supply prebiotic compounds to ubiquitous rocky planets, in search of the proper environment to start life in many places in the Universe. Under the heading of chemistry of the cometary nucleus, the following topics are covered: radial homogeneity of the nucleus; the dust-to-ice ratio; nature of the dust grains; origin of the dust in comets; nature of the volatile fraction; the CO distribution in comet Halley; dust contribution to the volatile fraction; elemental balance sheet of comet Halley; quantitative molecular analysis of the volatile fraction; and isotopic ratios. Under the heading of exogenous origin of carbon on terrestrial planets the following topics are covered: evidence for a high-temperature phase; from planetesimals to planets; a veneer of volatile and organic material; and cometary contribution.