3:30 PM - 5:00 PM
[PPS06-P13] Space weathering of crater ejecta and its dependency on crater size on the Moon
Keywords:Moon, space weathering, crater ejecta, crater ray
In this study, we determined the degree of space weathering of ejecta of lunar craters based on optical maturity parameter (OMAT) proposed by Lucey et al. (2000). Previous studies of crater rays (e.g., Werner and Medvedev, 2010) have proposed the dependency of the lifetime of crater ray on crater size, suggesting that the space weathering of crater ejecta is a function of the thickness and originated depth of ejecta. We investigated a-few-hundred-meter-sized and ten-kilometer-sized craters, that have been dated based on crater chronology and other methods by previous studies. Multi-band image data obtained by the Multi band Imager (MI) onboard the KAGUYA were used to analyze.
The results indicate that the ejecta of a-few-hundred-meter-sized craters is estimated to have matured by about 100 Ma, shorter than that of 10-kilometer-sized craters. Our results also indicate that the degree of space weathering is different by compositions in the area where the craters formed, suggesting that the effect of compositions should be considered when OMAT is used as an age indicator.
The results indicate that the ejecta of a-few-hundred-meter-sized craters is estimated to have matured by about 100 Ma, shorter than that of 10-kilometer-sized craters. Our results also indicate that the degree of space weathering is different by compositions in the area where the craters formed, suggesting that the effect of compositions should be considered when OMAT is used as an age indicator.