Processes governing the VIS/NIR spectral reflectance behavior of lunar swirlsстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 24 сентября 2020 г.
Аннотация:We investigated six bright swirls associated with magnetic anomalies of variable strength using Chandrayaan-1 Moon Mineralogy Mapper (M3) hyperspectral image data. We examined the 3 mkm absorption band generally ascribed to solar wind-induced OH/H2O and spectral trends in the near-infrared wavelength range at on-swirl and off-swirl locations. We found that the 3 mkm absorption band is weaker at on-swirl than at off-swirl locations and shows only weak variations with time-of-day. This result is consistent with magnetic anomaly shielding that reduces solar wind interaction with the surface. For a small swirl structure in Mare Moscoviense, we found the 3 mkm absorption band to be similar to that of its surroundings due to the absence of strong magnetic shielding. Our spectral analysis results at on-swirl and off-swirl locations suggest that the spectral trends at on-swirl and off-swirl locations cannot always be explained by reduced space-weathering alone. We propose that a combination of soil compaction possibly resulting from the interaction between the surface and cometary gas and subsequent magnetic shielding is able to explain all observed on-swirl vs. off-swirl spectral trends including the absorption band depth near 3 mkm. Our results suggest that an external mechanism of interactionbetween a comet and the uppermost regolith layer might play a significant role in lunar swirl formation.