Bright and dark polar deposits on Mercury: Evidence for surface volatiles

• Autores: Xiaoli Sun, Dandan Mao
• Localización: Science, ISSN 0036-8075, Vol. 339, Nº 6117, 2013, págs. 297-300
• Idioma: inglés
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• Resumen

  • Measurements of surface reflectance of permanently shadowed areas near Mercury’s north pole reveal regions of anomalously dark and bright deposits at 1064-nanometer wavelength. These reflectance anomalies are concentrated on poleward-facing slopes and are spatially collocated with areas of high radar backscatter postulated to be the result of near-surface water ice. Correlation of observed reflectance with modeled temperatures indicates that the optically bright regions are consistent with surface water ice, whereas dark regions are consistent with a surface layer of complex organic material that likely overlies buried ice and provides thermal insulation. Impacts of comets or volatile-rich asteroids could have provided both dark and bright deposits.