Oxygen is the dominant element in our planetary system. It is therefore remarkable that it shows substantial isotopic diversity both in mass-dependent fractionation, because it is a light element, and in mass-independent fractionation, primarily associated with variation in abundance of 16 O. On Earth, the primary variation in isotopic composition is related to temperature-dependent kinetic mass fractionation between hydrosphere and atmosphere. Meteorites provide samples of primitive bodies, that have not experienced melting, and planetesimals that have melted early in their history. Samples of Mars, Vesta, and the Moon are present in the meteorite collections. In meteorites, the cosmochemical fractionation related to the abundance of 16 O provides a useful classification scheme. Inclusions in chondrites show a large range in 16 O abundances from highly enriched (solar) through to compositions closer to terrestrial (planetary). The variability in 16 O appears originally to be related to predissociation and self-shielding of carbon monoxide likely in the primordial molecular cloud. Within the chondrite parent bodies, exchange between 16 O-poor fluids and relatively 16 O-rich solids created isotopic mixing lines. This model makes specific predictions for isotopic compositions of silicates and water ice throughout the solar system. One prediction, that the Earth should be isotopically heavier than the Sun, appears to be verified. But other tests based on oxygen isotopes within the solar system require either remote analysis or sample return missions. Remote analysis will require new instrumentation and analytical techniques to achieve the precision and accuracy required for three oxygen isotope analysis. Methodologies associated with cavity ring-down spectroscopy appear promising. Sample return appears viable only for the inner solar system including Mars and asteroids. While sample return missions to either Venus or Mercury appear highly challenging, the scientific benefits are immense both in oxygen isotope characterisation, and in a variety of other geochemical analyses. Measurement of three oxygen isotopes throughout the solar system would further our concepts for formation of other solar systems, and give us insight into the general mechanisms of planetary system formation and the role of water in the formation and evolution of the chondrite parent bodies and planets.

中文翻译：

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太阳系的氧同位素和采样

氧气是我们行星系统中的主要元素。因此，值得注意的是，它在质量相关分馏（因为它是一种轻元素）和质量独立分馏（主要与 16 O 丰度的变化有关）中都显示出大量同位素多样性。 在地球上，同位素组成的主要变化与水圈和大气之间的温度相关动力学质量分馏有关。陨石提供了原始天体的样本，它们没有经历过融化，以及在其历史早期融化的微星。火星、灶神星和月球的样本存在于陨石收藏中。在陨石中，与 16 O 丰度相关的宇宙化学分馏提供了一个有用的分类方案。球粒陨石中的内含物显示出从高度富集（太阳）到更接近陆地（行星）的成分的 16 O 丰度范围很大。16 O 的可变性最初似乎与可能在原始分子云中的一氧化碳的预解离和自屏蔽有关。在球粒陨石母体内，16 种贫氧流体和相对富含 16 种氧的固体之间的交换形成了同位素混合线。该模型对整个太阳系中硅酸盐和水冰的同位素组成进行了具体预测。一项关于地球同位素比太阳重的预测似乎得到了验证。但其他基于太阳系内氧同位素的测试需要远程分析或样本返回任务。远程分析将需要新的仪器和分析技术来实现三氧同位素分析所需的精密度和准确度。与腔衰荡光谱相关的方法似乎很有前景。样本返回似乎仅适用于包括火星和小行星在内的太阳系内部。虽然返回金星或水星的样本返回任务似乎极具挑战性，但在氧同位素表征和各种其他地球化学分析方面的科学利益是巨大的。测量整个太阳系的三种氧同位素将进一步加深我们对其他太阳系形成的概念，并使我们深入了解行星系统形成的一般机制以及水在球粒陨石母体和行星的形成和演化中的作用。