Primordial noble gases in micrometeorites and interplanetary dust

在所有元素中，惰性气体受发生在行星体内外的二次过程的影响最小；因此，它们在今天行星大气中的存量与它们在太阳系早期所获得的最为相似。在可能的来源中，也可能对其他挥发性元素或化合物（氮，水）做出重要贡献的是小行星和彗星体。今天撞击地球的地外物质主要以微陨石（mm，尺寸约为100 μm）的形式存在；然而，mm中稀有气体的丰度和同位素组成（除了注入的太阳风He和Ne）目前几乎是未知的。该项目的目的是分析mm中的所有稀有气体，并将元素和同位素丰度模式与太阳系其他已知储层的丰度模式进行比较。分析将使用带有多离子计数检测器的新型惰性气体质谱仪进行，首先必须优化气体提取和分离的程序。测量最终将扩展到包括在平流层中收集的更小的行星际尘埃颗粒（IDPs）。

Of all the elements, noble gases have been least affected by secondary processes taking place in and on planetary bodies; accordingly, their inventory in today’s planetary atmospheres resembles most closely that which they acquired in the early days of the Solar System. Among the possible sources, which also may have made an important contribution to other volatile elements or compounds (nitrogen, water), are asteroidal and cometary bodies. The main flux of extraterrestrial material hitting Earth today is in the form of micrometeorites (MMs; sizes on the order of 100 μm); however abundances and isotopic compositions of noble gases in MMs (with the exception of implanted solar wind He and Ne) are practically unknown at this time. The aim of the project is the analysis of all the noble gases in MMs and comparison of elemental and isotopic abundance patterns with those of other known Solar System reservoirs. Analyses will be performed using a new type of noble gas mass spectrometer with multi-ion counting detector, where procedures for gas extraction and separation will first have to be optimized. The measurements shall eventually be extended to include the even smaller interplanetary dust particles (IDPs) collected in the stratosphere.