JOVIAN SYSTEM DATA ANALYSIS PROGRAM PROPOSAL SUMMARY

Central objectives of proposal: Our science objectives are: (i) Map the spatial distribution of volcanic heat flow on the surface of Io, (ii) Analyze the temperature distributions of individual hot spots, (iii) Classify variations in spectral signature among hot spots, and (iv) Characterize temporal variability of hot spots. We will use Galileo NIMS (Near-Infrared Mapping Spectrometer) data to analyze the thermal output of Io's volcanic areas over time to achieve these four science objectives. The new data from Galileo, particularly from the NIMS instrument, provide an unprecedented opportunity to pursue our science objectives. Galileo has obtained, for the first time, observations from which we can measure Io's volcanic heat flow on the scale of 100 to 500 km on the surface, over time scales ranging from minutes to nearly two years. It is now possible to study the spatial characteristics and temporal variability of Io's volcanism, which reflect the planet's interior heating and how magma is transported from the interior to the surface. Significant improvements in the algorithms for analyzing NIMS data have recently been achieved. The most notable are the ability to remove spacecraft and instrument induced patterns that dominate the spectra of the hot spots on Io, and the ability to use these patterns to separate reflected and thermal components of the spectra. This breakthrough allows us to obtain temperatures of hotspots from daytime observations, thus enabling us to correlate data across all orbits of Galileo. The pattern removal also makes possible to identify minor absorption bands in Io's spectra. The results of our first science objective (map the spatial distribution of volcanic heat flow on a global scale) will be used to help distinguish between two major tidal dissipation models for Io, as these models predict distinctly different heat flow patterns on Io's surface. The results of our second objective (analyze the temperature distribution within hotspots) will be used to identify possible different styles of volcanic activity taking place on Io. The results of our third objective (classify variations in spectral signatures among hotspots) will be used to understand the composition of Io's pristine surface near hotspots and to identify new species associated with active volcanism. The results of our fourth objective (characterize the temporal variability of hotspots) will be used to identify persistent and sporadic types of hotspots, to test the stability of regional fluxes, to estimate volcanic cooling and resurfacing rates, and to constrain eruption rates and magma supply rates. Products resulting from the analyses will include de-patterned NIMS data, and NIMS data cubes in which reflected and emitted components of the spectra have been separated, and maps of thermal output measured by NIMS. These data will be made available to the science community for use in JSDAP analyses. Significance: This proposal addresses NASA's Office of Space Science (OSS) interests in volcanic processes. Volcanism is one of the fundamental geological processes in the evolution of solid bodies. Io is the only solid body outside the Earth where active, large-scale volcanism has been observed. Io's extraordinarily high rates of volcanism and heat flow make it an ideal laboratory for studying planetary volcanism and for providing a window into the possible processes which operated in the ancient Earth, Mars, Venus, the Moon and, possibly, Mercury. The proposed work will provide the most complete view to date of the temporal and spatial variability of Io's volcanic eruptions, which will be key to placing new constraints on Io's interior and on the processes driving Ionian eruptions. Summary of education and outreach plan: We propose to use Io as the centerpiece for a video showing how the skills taught in schools (K-12) and community colleges can be applied to the challenge of space exploration. Our partners in the Education and Outreach proposal are the College of the Sequoias and the Math Engineering Science Achievement California Community College Programs (MESA CCCP).