The Geographic Distribution of Dense-phase O₂ on Ganymede

Abstract Ground-based spectroscopy of Ganymede’s surface has revealed the surprising presence dense-phase molecular oxygen (O 2 ) via weak absorptions at visible wavelengths. To date, state and stability this O temperatures pressures are not understood. Its spatial distribution in relation to albedo, expected temperatures, particle irradiation patterns, or composition may provide clues these unknowns. We present spatially resolved observations obtained with Hubble Space Telescope construct first comprehensive map its geography. In agreement limited data published previously, our suggests that condensed is concentrated low midlatitudes trailing hemisphere, a reflect influences intrinsic magnetic field on bombardment by Jovian magnetospheric particles. Overlapping regions from different within set also show evidence for moderate temporal variability , but we unable distinguish between potential causes available data.