Isotopic evidence of long-lived volcanism on Io

Abstract

Jupiter's moon Io hosts extensive volcanism driven by tidal heating. The isotopic composition of Io's inventory of volatile elements, including sulfur and chlorine, reflects its outgassing and mass loss history and provides an avenue for exploring 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 ${}^{34}$S/${}^{32}$S=0.0595$\pm$0.0038 (${\delta }^{34}$S=+347$\pm$86 per mille), 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 ${}^{37}$Cl/${}^{35}$Cl=0.403$\pm$0.028 (${\delta }^{37}$Cl=+263$\pm$88 per mille) shows chlorine is similarly enriched. These measurements 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.

arXiv commentThis is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on May 10, 2024, DOI: 10.1126/science.adj0625

References in corpus (9)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• emcee: The MCMC Hammer
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• A Primordial Origin of the Laplace Relation Among the Galilean Satellites
• Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy)
• Formation of Giant Planet Satellites
• The ALMA Interferometric Pipeline Heuristics
• Exploring Io's atmospheric composition with APEX: first measurement of 34SO2 and tentative detection of KCl

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