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Descrizione
Recent observations by the JIRAM instrument onboard NASA's Juno mission have fundamentally revised our understanding of Io's interior structure and global thermal budget. We present two major results from JIRAM infrared imaging of Io's hot spots.
On 27 December 2024, JIRAM captured a multi-hotspot eruption in Io's southern hemisphere covering approximately 65,000 km². The event produced 140–260 TW, more than three orders of magnitude above prior estimates and likely exceeding the brightest eruption ever recorded on Io. Three adjacent hot spots brightened simultaneously, and temperature analysis demonstrates a synchronous onset, implying a single eruptive event propagating laterally beneath the surface across hundreds of kilometers. This is the first time such behavior has been observed on Io, pointing to a system of massive interconnected subsurface magma reservoirs whose topology may resemble a large-scale sponge, with reservoirs connected through a largely solid outer shell.
A systematic analysis of thirty lava lakes identified by JIRAM reveals that the dominant thermal contribution comes from their low-temperature central crusts rather than from the hotter peripheral rings, implying that previous power estimates were underestimated by up to a factor of ten. Io's paterae undergo stochastic resurfacing on timescales of roughly a decade, with crust temperature serving as a proxy for the evolutionary state of each lake. Together, these results indicate that current assessments of Io's global heat flux are significant underestimates, and that only full-surface high-resolution infrared observation can yield a realistic value for the moon's total thermal output, with direct implications for tidal dissipation models.
| Sessione | Sistema Solare e astrobiologia |
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