Quantification of Io’s Volcanic Heat Flow from Galileo NIMS Data to Inform a Return to Io

Abstract:

We have been processing all Io spectral radiance data obtained by Galileo’s Near Infrared Mapping Spectrometer (NIMS) to derive at-surface leaving radiances for over 1000 detections of thermal emission from Io’s active volcanoes. This has allowed robust quantification of thermal emission from the 115+ volcanoes detected by NIMS. Products will be made available via NASA’s Planetary Data System (PDS). In processing all suitable NIMS Io “tube” products, we have found some new hot spot thermal emission detections, including from Loki Patera. NIMS data contain the highest spatial and spectral resolution data of thermal emission from Io’s active volcanoes [e.g., 1] but historically have been hard to access and process. Data access has recently been improved [2]. Now, the fully processed NIMS spectra, as PDS products, will allow wider planetary community access to an invaluable resource: an extensive set of Io’s volcanic thermal emission spectra. These products enable deeper data analysis, and also comparison with contemporaneous data obtained with ground-based telescopes [3]. These data provide insight into volcanic processes on Io, including the derivation of eruption style – the manner in which lava is discharged on to Io’s surface [e.g., 4]. Understanding discharge mechanism and the resulting surface temperature and area distributions supports accurate design of observations by Io Volcano Observer, a Discovery-class mission concept finalist [5]. “Follow the heat” is the overarching strategy of IVO. If selected, IVO would answer the most pressing questions about tidal heating, a fundamental process affecting satellites across the solar system [6]. Acknowledgements: We thank the NASA PDART Program for support. This work was performed at JPL and BFI under NASA contract. References: [1] Davies, A. G. Volcanism on Io, CUP, 372 pages. 2007. [2] Cahill, J. et al., 3rd Plan. Data Workshop, abs.7071. 2017. [3] Davies, A. G. et al. GRL, 39, L01201. 2012. [4] Davies, A. G. et al., 2010 JVGR, 194, 75-99. [5] McEwen, A. S. et al., LPSC 50, Abstract 1316, 2019. [6] de Kleer, K. et al. https://www.kiss.caltech.edu/final_reports/Tidal_Heating_final_report.pdf, 2019.