Hoppe Peter, Rubin Martin, Altwegg Kathrin
Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
Space Sci Rev. 2018;214(6):106. doi: 10.1007/s11214-018-0540-3. Epub 2018 Sep 6.
Comets are considered the most primitive planetary bodies in our Solar System, i.e., they should have best preserved the solid components of the matter from which our Solar System formed. ESA's recent Rosetta mission to Jupiter family comet 67P/Churyumov-Gerasimenko (67P/CG) has provided a wealth of isotope data which expanded the existing data sets on isotopic compositions of comets considerably. In this paper we review our current knowledge on the isotopic compositions of H, C, N, O, Si, S, Ar, and Xe in primitive Solar System materials studied in terrestrial laboratories and how the Rosetta data acquired with the ROSINA (Rosetta Orbiter Sensor for Ion and Neutral Analysis) and COSIMA (COmetary Secondary Ion Mass Analyzer) mass spectrometer fit into this picture. The H, Si, S, and Xe isotope data of comet 67P/CG suggest that this comet might be particularly primitive and might have preserved large amounts of unprocessed presolar matter. We address the question whether the refractory Si component of 67P/CG contains a presolar isotopic fingerprint from a nearby Type II supernova (SN) and discuss to which extent C and O isotope anomalies originating from presolar grains should be observable in dust from 67P/CG. Finally, we explore whether the isotopic fingerprint of a potential late SN contribution to the formation site of 67P/CG in the solar nebula can be seen in the volatile component of 67P/CG.
彗星被认为是我们太阳系中最原始的行星天体，也就是说，它们应该最完好地保存了太阳系形成时物质的固体成分。欧洲航天局最近对木星族彗星67P/丘留莫夫－格拉西缅科彗星（67P/CG）执行的罗塞塔任务提供了大量同位素数据，极大地扩充了关于彗星同位素组成的现有数据集。在本文中，我们回顾了目前在地面实验室对原始太阳系物质中氢、碳、氮、氧、硅、硫、氩和氙的同位素组成的了解，以及利用ROSINA（罗塞塔轨道器离子与中性分析传感器）和COSIMA（彗星二次离子质谱仪）质谱仪获取的罗塞塔数据如何与这一情况相契合。67P/CG彗星的氢、硅、硫和氙同位素数据表明，这颗彗星可能特别原始，可能保存了大量未经过处理的前太阳物质。我们探讨了67P/CG彗星的难熔硅成分是否包含来自附近II型超新星（SN）的前太阳同位素指纹，并讨论了在67P/CG彗星尘埃中，源自前太阳颗粒的碳和氧同位素异常在多大程度上应该是可观测到的。最后，我们探究了在67P/CG彗星的挥发性成分中，是否能看到潜在的晚期超新星对67P/CG彗星在太阳星云形成地点贡献的同位素指纹。
