Heavy noble gases in solar system matter
Heavy noble gases in solar system matter
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太阳系中的重惰性气体物质
DOI：
10.1111/j.1945-5100.2002.tb01102.x
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
K. Marti
中科院分区：
文献类型：
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作者：
K. Marti
~ClO·12...J.……L！不是IJL。2 S...~·4E测定直接收集到的太阳风稀有气体，这项任务目前正在进行中。太阳粒子注入的时间必须通过对风化层历史的详细研究来推断。作为太阳元素丰度和同位素丰度参考物质的原始球粒陨石不能用于惰性气体，因为相对元素丰度相对于太阳中的元素丰度是强烈亏损的(见图1)，并且它们的同位素特征随太阳风数据而变化。这些气体是如何融入行星材料的？木星上的航天器证实，最大的行星在其大气层中吸收并保留了接近太阳比例的惰性气体。金星、地球和火星的大气层以及原始的球粒陨石显示出较轻的稀有气体的损耗因子约为一百万倍甚至更多(见图1)。在火星的情况下，元素丰度和同位素丰度的大气特征与固体行星的大气特征之间存在重大差异(例如，Bogard等人，2001年)。虽然在火星内部观察到了Xe的太阳类型的Xe同位素特征(Mathew和Marti，2001)，但这个特征还没有(或者还没有？)在固体地球上被观测到。另一方面，这两颗行星的大气氙气同位素特征非常相似(相对于太阳Xe，每质量单位-3.7%)，有利于重同位素。TOM中的球粒陨石显示出相当均匀的氙组分(OC-Xe)，这不可能与依赖质量的分馏机制的太阳信号有关(Lavielle和Marti，1992)。中的重惰性气体
~ Cl o · 12 ...J .. ..!l! o IJl . 2 s.. .~ · 4 E e determinations ofdirectly collected solar wind noble gases by the GENESIS mission, which is currently in progress. The timing of solar particle implantation has to be inferred from detailed studies of the regolith histories . The primitive chondritic meteorites, which serve as reference materials for solar elemental and isotopic abundances, can not be used for noble gases since the relative elemental abundances are strongly depleted relative to those in the Sun (see Fig. 1), and their isotopic signatures are at variation with solar wind data . How were these gases incorporated into planetary materials? The largest planets incorporated and retained noble gases in nearly solar proportions in their atmospheres, as verified by spacecraft on Jupiter. The atmospheres of Venus, Earth and Mars, as well as primitive chondritic meteorites show depletion factors of about a million and more for the lighter noble gases (see Fig. 1). In the case of Mars major differences are found between atmospheric signatures and those of the solid planet for both elemental and isotopic abundances (e.g ., Bogard et al., 2001). While a solar-type xenon isotopic signature was observed for Xe in the interior of Mars (Mathew and Marti, 2001), this signature has not (or not yet?) been observed for solid Earth. On the other hand, the atmospheric xenon isotopic signatures of both planets were rather similarly fractionated (by -3.7% per mass unit relative to solar Xe) in favor of the heavy isotopes. The chondritic meteorites in tum show a rather uniform xenon component (OC-Xe) which can not be related to the solar signature by a mass-dependent fractionation mechanism (Lavielle and Marti, 1992). Heavy noble gases in