講演情報
[PCG24-05]Search of CH4 on Mars by SOFIA/EXES
青木 翔平2、*中川 広務1、笠羽 康正1、佐川 英夫3、Richter Matthew4、DeWitt Curtis4 (1.東北大学 大学院理学研究科 地球物理学専攻太陽惑星空間物理学講座 惑星大気物理学分野、2.Institut d'Aéronomie Spatiale de Belgique、3.京都産業大学、4.Physics Department, UC Davis)
キーワード：
火星、メタン、SOFIA
Discovery of CH4 in the Martian atmosphere has led to much discussion since it could be a signature of biological/geological activities on Mars. However, the presence of CH4 and its temporal and spatial variations are still under discussion. We performed sensitive measurements of Martian CH4 by using the Echelon-Cross-Echelle Spectrograph (EXES) onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) on 16 March 2016, which corresponds to summer (Ls = 123.2°) in the northern hemisphere on Mars. The high altitude of SOFIA telescope (~13.7 km) enables us to significantly reduce the effects of terrestrial atmosphere, and the high spectral resolution of EXES (R~90,000) enables us to detect the intrinsically narrow lines of Martian CH4 at the 7.5 μm band. . Mars disk was spatially resolved into 3 x 3 areas, none of the observed region showed the unambiguous detections of CH4. The upper limits on the CH4 volume mixing ratio ranges from 1 to 6 ppb.