发表机构
Univ Paris Est Creteil and Université Paris Cité, CNRS, LISA; IJCLab, CNRS, Université Paris-Saclay; LPC2E, OSUC, Univ Orleans, CNRS, CNES; Universität der Bundeswehr München; Catholic University of America（巴黎东克雷泰伊大学和巴黎西岱大学; 巴黎萨克雷大学; 奥尔良大学; 慕尼黑联邦国防军大学; 美利坚天主教大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过比较彗星67P尘埃颗粒表面与次表面成分，发现表面金属亏损源于吸积前太阳风辐照，并提出了组分运输与混合形成彗核的机制。
AI 中文摘要
彗星被认为在很大程度上保留了其形成时的原始物质。因此，彗星研究为太阳系形成所涉及的过程提供了重要线索。在欧空局罗塞塔任务的最后几周，COSIMA（彗星二次离子质谱分析仪）仪器进行了一系列测量，涉及对从彗星67P/Churyumov-Gerasimenko捕获的尘埃颗粒进行长期溅射。这些溅射后分析揭示了8个颗粒的次表面成分，我们将其与59个未溅射颗粒碎片表面的9种元素成分进行了比较。我们发现，所分析的表面与太阳丰度相比，在金属（如Mg和Fe）方面强烈亏损，而次表面物质与太阳值一致。由于COSIMA捕获的尘埃在与收集靶碰撞时碎裂，这种金属亏损不能仅存在于整体颗粒的外表面。相反，这些亏损层必须覆盖在更小的、未碎裂的矿物亚单元表面。这种亏损层通常被称为“边缘”，在太阳系无空气天体上发现的小型风化层尘埃颗粒表面很常见，并归因于太空风化。我们认为，这些矿物彗星亚单元在太阳系形成早期经历了太阳星云内部区域的吸积前太阳风辐照。然后，这些被辐照的小尘埃组分必须被输送到太阳星云的外部区域，在那里它们与冰混合形成彗星的核。
英文摘要
Comets are thought to have largely preserved the primordial material from which they formed. Therefore, cometary studies provide important clues about the processes involved in the formation of the Solar System. During the last weeks of ESA's Rosetta mission, the COSIMA (COmetary Secondary Ion Mass Analyser) instrument performed a series of measurements, which involved long-term sputtering of dust particles captured from comet 67P/Churyumov-Gerasimenko. These post-sputtering analyses revealed the subsurface composition of 8 particles, which we compare here with surfaces composition measured on 59 un-sputtered particle fragments for 9 elements. We found that the analysed surfaces are strongly depleted in metals, such as Mg and Fe, compared to solar abundances, while the subsurface material is consistent with solar values. Because the dust captured by COSIMA fragmented upon impact with the collection targets, this metal depletion cannot reside exclusively on the outer surface of the bulk particles. Instead, these depletion layers must coat the surface of smaller, unfragmented mineral subunits. Such depletion layers, which are often called 'rims', are common at the surface of small regolith dust particles found on airless bodies in our solar system and are attributed to space weathering. We suggest that these mineral cometary subunits experienced pre-accretional solar wind irradiation in the inner regions of the solar nebula during the early stages of Solar System formation. The small irradiated dust constituents must then have been transported to the outer regions of the solar nebula, where they mixed with ices to form the nucleus of the comet.
