Isotopic evidence of long-lived volcanism on Io

• 成果类型: Article
• 署名作者: de Kleer, Katherine; Hughes, Ery C.; Nimmo, Francis; Eiler, John; Hofmann, Amy E.; Luszcz-Cook, Statia; Mandt, Kathy
• 署名单位: California Institute of Technology; GNS Science - New Zealand; University of California System; University of California Santa Cruz; National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; New York University; Columbia University; American Museum of Natural History (AMNH); National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13852
• DOI: 10.1126/science.adj0625
• 发表日期: 2024-05-10
• 页码: 682-687
• 关键词: microwave-spectrum; driven atmosphere; sulfur isotopes; wave spectrum; hale-bopp; chlorine; photochemistry; spectroscopy; millimeter; fractionation

摘要

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 submillimeter observations of Io's atmosphere to measure sulfur isotopes in gaseous sulfur dioxide and sulfur monoxide, and chlorine isotopes in gaseous sodium chloride and potassium chloride. We find S-34/S-32 = 0.0595 +/- 0.0038 (equivalent to delta S-34 = +347 +/- 86 parts per thousand), 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 Cl-37/Cl-35 = 0.403 +/- 0.028 (delta Cl-37 = +263 +/- 88 parts per thousand) 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.