The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets
The Provenances of Asteroids, and Their Contributions to the Volatile Inventories of the Terrestrial Planets
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DOI：
10.1126/science.1223474
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发表时间：
2012-08-10
期刊：
影响因子：
56.9
通讯作者：
Nittler, L. R.
中科院分区：
文献类型：
--
作者：
Alexander, C. M. O'D.;Bowden, R.;Nittler, L. R.
确定地球吸积的氢、碳和氮的来源(S)对于了解水和生命的起源以及限制行星形成过程中的动力学过程非常重要。球粒陨石是小行星碎片，保留了太阳系最初几百万年历史的记录。碳质球粒陨石中水的氚/氢(D/H)值与彗星和土星卫星土卫二中的值不同，这意味着它们形成于太阳系的不同区域，与最近的动力学模型的预测相反。碳质球粒陨石中水的D/H值也反对来自外太阳系的水冰流入，这被用来解释内太阳系的非太阳氧同位素组成。CI球粒陨石的氢和氮同位素组成表明，它们是地球挥发物的主要来源。
Determining the source(s) of hydrogen, carbon, and nitrogen accreted by Earth is important for understanding the origins of water and life and for constraining dynamical processes that operated during planet formation. Chondritic meteorites are asteroidal fragments that retain records of the first few million years of solar system history. The deuterium/hydrogen (D/H) values of water in carbonaceous chondrites are distinct from those in comets and Saturn's moon Enceladus, implying that they formed in a different region of the solar system, contrary to predictions of recent dynamical models. The D/H values of water in carbonaceous chondrites also argue against an influx of water ice from the outer solar system, which has been invoked to explain the nonsolar oxygen isotopic composition of the inner solar system. The bulk hydrogen and nitrogen isotopic compositions of CI chondrites suggest that they were the principal source of Earth's volatiles.