[M-IS07] アストロバイオロジー

[MIS07-06] Prospects for the Detection of Photosynthetic Biosignatures from Extrasolar Planets

★Invited Papers

*小松 勇¹ (1.アストロバイオロジーセンター / 国立天文台)

キーワード：太陽系外惑星、バイオシグネチャー、光合成、アストロバイオロジー

More than 5,000 extrasolar planets (exoplanets) have been discovered, and future observations will discover habitable planets, planets with liquid water on their surfaces. Current observations use spectroscopy to characterize exoplanet atmospheres, and biosignatures, i.e., traces of life activity, are expected to be detected in the future [1, 2]. The challenge, however, is to bridge the gap between the identification of potential biosignatures and the definitive detection of life [3]. The assumption that life on a planet involves the acquisition of energy through metabolism makes the detection of traces of such activity a crucial indicator of life on exoplanets. Therefore, the detection of traces of this activity is a clue to the detection of life. Among Earth's known metabolisms, photosynthesis is highlighted as a key element for future astronomical observations of exoplanets [4], since photosynthesis has radically altered Earth's environment. Atmospheric molecules such as oxygen and surface features such as the vegetation red edge are considered biosignatures. However, the non-biological explanations for each signal require the accumulation of circumstantial evidence, using assumptions based on terrestrial organisms, and interdisciplinary discussions. Based on these considerations, researches on photosynthesis on exoplanets are presented for future discussion [5, 6].


References
[1] Schwieterman, E. W. et al.: 2018, Astrobiology, 18, 663-708. [2] Fujii, Y. et al.: 2018, Astrobiology,39, 233–251. [3] Meadows V. S. et al.: 2022, arxiv,2022.10. [4] Kiang, N. Y. et al.: 2007, Astrobiology, 7, 252-274. [5] Komatsu, Y. et al.: 2023, The Astrophysical Journal, 942, 22. [6] Komatsu, Y.: 2023, Viva Origino 51(3).