Experimental and theoretical formation of Martian penitentes

Abstract

This research aims to investigate the possibility of penitente formation on Mars. Penitentes are blade like structures with spikes formed in snow or ice in cold dry environments with strong solar insolation due to self illumination causing differential ablation. As penitentes house life in extreme environments on Earth they are potential locations where extraterrestrial life could exist or has existed on Mars. To investigate the formation of Martian penitentes experiments have been performed that simulate the Martian temperatures, pressures and solar insolation, and a theoretical model was used to calculate the possible growth rate and penitente spacing at certain location on Mars. While no penitentes were able to form on their own during the experiments the key attributing factors for penitente formation were found: the temperature, pressure and kind of ablation material. Theoretically penitente formation on Mars is possible at Olympus Mons, Elysium Mons, Arsia Mon and Alba Mons. The growth of penitentes at these locations would take several years if the temperature and pressure remained stable. However the temperatures and pressures do not remain stable resulting is strong sublimation when temperatures rise. In the South polar region penitente formation is possible and remain stable as formation conditions are reached when the maximum temperature in that region is reached. However CO2 snow covers the South polar region during local winter which may disrupt micro-penitentes formed during the summer. Thus while penitente formation is possible on modern Mars insufficient time is available to grow visible penitentes unless a CO2 snow cover does not disrupt preformed penitentes.