[M-IS08] アストロバイオロジー

[MIS08-02] Ultraviolet observation of terrestrial exoplanets using future space telescopes and beyond

★Invited Papers

*亀田 真吾¹、中山 陽史¹、桑原 正輝¹、岸田 真於¹、小玉 貴則²、村上 豪³、生駒 大洋⁴、寺田 直樹⁶、成田 憲保⁵、塩谷 圭吾³ (1.立教大学理学部、2.地球生命研究所、東京科学大学、3.宇宙航空研究開発機構宇宙科学研究所、4.国立天文台 科学研究部、5.東京大学、6.東北大学大学院理学研究科)

キーワード： 系外惑星、宇宙望遠鏡、惑星大気

Many Earth-sized planets have already been discovered, and several Earth-like planets have been detected in the habitable zone of low-mass stars near the solar system. Transit spectroscopy is an effective method for observing atmospheres, but it requires extremely high precision to observe the thin lower atmospheres of small terrestrial planets, and at present no atmospheres of terrestrial exoplanets have been detected. On the other hand, low-mass stars have very strong XUV radiation even in the habitable zone, which may cause the upper atmospheres of terrestrial planets to extend to more distant regions with high density. In this study, we investigate the possibility of detecting the upper atmospheres of terrestrial exoplanets by transit spectroscopic observations with future ultraviolet space telescopes. There are several atomic and ionic emission lines (H, C, N, and O) in the far UV spectral range. Though we could not immediately conclude that the exoplanet has an ocean even if we detect H and O upper atmosphere, The results of the observations will provide important information for understanding the lower atmosphere and surface environment especially in case the lower atmosphere of the exoplanet cannot be detected.
In this presentation, we introduce the current status of our activity on UV observation using future UV space telescopes and the UV instrument technology development. In addition, we discuss a future plan on exoplanet observation and solar system exploration.