14:15 〜 14:30
[MIS19-03] リモートセンシング解析による火星高緯度域の液体塩水の存否検証
キーワード：火星、高緯度域、Dark Dune Spot、液体塩水、リモートセンシング解析
The present-day Martian surface is a low-temperature and low-pressure environment, so pure water cannot exist in a liquid state. On the other hand, thermodynamic models suggest that liquid brines (such as perchlorate and other salts) may form and persist on the high-latitude surface of Mars (Rivera-Valentin et al., 2020). If liquid brine exists on the Martian surface, then there is a possibility that life may exist, which is important for the future search for extraterrestrial extant life. However, observational data supporting the presence of liquid brine have not been obtained yet.
In this study, we focus on the Dark Dune Spots (DDS) observed at southern high-latitudes, appearing to form a liquid-like state from spring to summer (Kereszturi et al., 2011). We attempt to verify the possible existence of liquid brine by analyzing the seasonal variation in the chemical composition of the DDS regions by remote sensing analysis using CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) data.
Seasonal variations in the CRISM spectral pattern reveal that the abundance of CO2 ice on the surface changes significantly as; (1) CO2 ice decreases from spring to early summer due to sublimation, (2) completely disappears from early summer to early fall, and (3) condenses on the surface again in early winter. During the summer solstice, the spectral absorption is not clear, but weak spectral absorptions of gypsum and hydrated minerals are observed. We will further perform spectral analysis of the DDS regions to verify the possible existence of liquid brine at Martian high latitudes.
In this study, we focus on the Dark Dune Spots (DDS) observed at southern high-latitudes, appearing to form a liquid-like state from spring to summer (Kereszturi et al., 2011). We attempt to verify the possible existence of liquid brine by analyzing the seasonal variation in the chemical composition of the DDS regions by remote sensing analysis using CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) data.
Seasonal variations in the CRISM spectral pattern reveal that the abundance of CO2 ice on the surface changes significantly as; (1) CO2 ice decreases from spring to early summer due to sublimation, (2) completely disappears from early summer to early fall, and (3) condenses on the surface again in early winter. During the summer solstice, the spectral absorption is not clear, but weak spectral absorptions of gypsum and hydrated minerals are observed. We will further perform spectral analysis of the DDS regions to verify the possible existence of liquid brine at Martian high latitudes.