Researchers at the Astrobiology Center (ABC) of National Institutes of Natural Science (NINS) in Japan and their colleagues have proposed a prediction that red-edge could be observed as on the Earth even on exoplanets around M-dwarfs. They pointed out that the first oxgenic photorophs are most likely to have evolved underwater to utilize visible light just like what had happened in the primordial ocean on the Earth. They examined light adaptation mechanisms of visible- and IR-radiation-using phototrophs required for adapting to land habitats and found out that IR-using phototrophs struggle to adapt to changing light condition at the boundary of water and land surface.
M-dwarfs or red dwarfs are small (0.5-0.1 solar-masses) and cool ( ~3000 Kelvin) stars, and are abundant in universe. The Sun-like stars have been attracting most attention as a plausible target for searching habitable exoplanets. However, nearby M-dwarfs are becoming the most extensive targets for habitable planet searches because they are the most abundant nearby stars and thus could be the first candidate for detecting any biosignatures on exoplanets via transit or direct imaging observations in near future.To read more, click here.