Superflares UV impact on the habitability of exoplanets
Tipo
Capítulo de livro
Data de publicação
2021
Periódico
Ultraviolet Astronomy and the Quest for the Origin of Life
Citações (Scopus)
0
Autores
Estrela R.
Valio A.
Valio A.
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Resumo
© 2021 Elsevier Inc. All rights reserved.The habitability of a planet can be severely affected by the activity of its host star. Several young solar-type and fully convective stars observed by the Kepler mission produce superflares that are up to 1000 times more energetic than those of the Sun. These superflares can increase the level of UV irradiation received by the planet. Thus, if there is no atmosphere capable of attenuating this UV flux, life present on the planet surface will be at risk. In this chapter we analyze the impact of the UV radiation from these superflares on living organisms on the surface or in the ocean of orbiting planets in the habitable zone of the star. Two active stars are analyzed here, Kepler-96 (solar-type) and TRAPPIST-1 (M-dwarf). Both stars generate powerful flares in short timescales. Kepler-96 harbors a Super-Earth orbiting very close to the star, impossible to be habitable due to its proximity to the star. Nevertheless, its age of 2.3 Gyr is the same as the Sun when the first multicellular organisms appeared on Earth, that increased considerably the oxygen in Earth’s atmosphere. The TRAPPIST-1 system consists of seven terrestrial planets, three of them in the habitable zone of the star. The estimated UV flux produced by the superflares of both stars implies that life would only survive on the surface of these planets if there was already an ozone layer present on the planet atmosphere. If that is not the case, life.