据了解，木星的卫星木卫一上有大量的火山活动，这是由潮汐加热驱动的。木卫一上挥发性化学元素的同位素组成，包括硫和氯，反映了它的放气和质量损失历史，并记录了它的演化信息。
课题组人员对木卫一大气进行毫米尺度观测，测量气态SO2和SO中的硫同位素，气态NaCl和KCl中的氯同位素。该研究团队发现34S/32S = 0.0595±0.0038(相当于δ34S = +347±86‰)，与太阳系的平均值相比，它是高富集的，这表明木卫一已经损失了94-99%的有效硫。测量值为37Cl/35Cl = 0.403±0.028 (δ37Cl = +263±88‰)，表明氯同样富集。
这些结果表明，木卫一在其大部分(或全部)历史中都有火山活动，在早期可能有更高的排气和质量损失率。
附：英文原文
Title: Isotopic evidence of long-lived volcanism on Io
Author: Katherine de Kleer, Ery C. Hughes, Francis Nimmo, John Eiler, Amy E. Hofmann, Statia Luszcz-Cook, Kathy Mandt
Issue&Volume: 2024-04-18
Abstract: Jupiter’s moon Io hosts extensive volcanism, driven by tidal heating. The isotopic composition of Io’s inventory of volatile chemical elements, including sulfur and chlorine, reflects its outgassing and mass loss history, and thus records information about its evolution. We used millimeter observations of Io’s atmosphere to measure sulfur isotopes in gaseous SO2 and SO, and chlorine isotopes in gaseous NaCl and KCl. We find 34S/32S = 0.0595 ± 0.0038 (equivalent to δ34S = +347 ± 86‰), which is highly enriched compared to average Solar System values and indicates that Io has lost 94 to 99% of its available sulfur. Our measurement of 37Cl/35Cl = 0.403 ± 0.028 (δ37Cl = +263 ± 88‰) shows that chlorine is similarly enriched. These results indicate that Io has been volcanically active for most (or all) of its history, with potentially higher outgassing and mass-loss rates at earlier times.
DOI: adj0625
Source: https://www.science.org/doi/10.1126/science.adj0625