Primitive objects like comets hold important information on the material that formed our solar system. Several comets have been visited by spacecraft and many more have been observed through Earth- and space-based telescopes. Still our understanding remains limited. Molecular abundances in comets have been shown to be similar to interstellar ices and thus indicate that common processes and conditions were involved in their formation. The samples returned by the Stardust mission to comet Wild 2 showed that the bulk refractory material was processed by high temperatures in the vicinity of the early sun. The recent Rosetta mission acquired a wealth of new data on the composition of comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) and complemented earlier observations of other comets. The isotopic, elemental, and molecular abundances of the volatile, semi-volatile, and refractory phases brought many new insights into the origin and processing of the incorporated material. The emerging picture after Rosetta is that at least part of the volatile material was formed before the solar system and that cometary nuclei agglomerated over a wide range of heliocentric distances, different from where they are found today. Deviations from bulk solar system abundances indicate that the material was not fully homogenized at the location of comet formation, despite the radial mixing implied by the Stardust results. Post-formation evolution of the material might play an important role, which further complicates the picture. This paper discusses these major findings of the Rosetta mission with respect to the origin of the material and puts them in the context of what we know from other comets and solar system objects.

中文翻译：

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论67P/Churyumov-Gerasimenko中素材的起源和演变


像彗星这样的原始物体保存着有关形成太阳系的物质的重要信息。航天器已经访问了几颗彗星，通过地球和太空望远镜观察到了更多彗星。我们的理解仍然有限。彗星中的分子丰度已被证明与星际冰相似，因此表明它们的形成涉及共同的过程和条件。星尘号任务返回维尔德 2 号彗星的样本显示，散装耐火材料是在早期太阳附近经过高温处理的。最近的罗塞塔任务获得了有关 67P/Churyumov-Gerasimenko 彗星（以下简称 67P/CG）成分的大量新数据，并补充了早期对其他彗星的观测。挥发性、半挥发性和难熔相的同位素、元素和分子丰度为掺入材料的起源和加工带来了许多新的见解。罗塞塔号之后出现的情况是，至少部分挥发性物质是在太阳系之前形成的，并且彗星核在日心距离的很大范围内聚集，这与今天发现的地方不同。与太阳系整体丰度的偏差表明，尽管星尘结果暗示了径向混合，但彗星形成位置的物质并未完全均质化。材料形成后的演化可能发挥重要作用，这使情况进一步复杂化。本文讨论了罗塞塔任务有关材料起源的这些主要发现，并将它们置于我们从其他彗星和太阳系物体中了解的背景中。