Ionian Volcanoes Reveal Their Temperatures

Introduction: Cassini ISS imaged the surface of Io in eclipse by Jupiter in late 2000 and early 2001 and obtained multiple-filter images over timescales of hours. Images like these have been used to study the temperature and variability of the numerous hotspots on the surface [1, 2, 3]. For example, Pele was found to be an active lava lake with most likely basaltic lava composition [2]. New Horizons data suggests temperatures of 1150 K to 1335 K for the brightest hotspots [4]. We undertook similar color temperature analyses to determine the lava composition and eruption style of three hotspots (Figure 1): Pillan, Wayland, and Loki.