Stars, life, and planetary habitability

ABREVAYA, X.C.

Jornada; 2nd-latin-america-colloquium NoRCEL; 2023

NORCEL

The concept of habitability allows delimitating which places in the universe could be suitable to sustain life. Planetary habitability in particular can be defined as the “ability of an environment to support the activity of at least one known organism”. As the planetary environment is influenced by the host star the star-planet interaction has to be considered in habitability studies. Stellar activity plays a fundamental role in shaping the planetary conditions and stellar radiation appears as one of the fundamental factors to be studied, as it can be beneficial or detrimental for life through direct or indirect effects. Particularly, UV radiation wavelengths (200-400 nm) can reach the surface of the planet depending on the atmospheric composition and pressure. Very energetic stellar events such as flares and superflares have been scarcely studied from the biological point of view and are of high relevance since the high UV fluxes that are emitted during these processes could have an impact on life on the surface of a planetary body. Some previous studies in the topic have been using theoretical approaches employing biological data from the literature to determine the of flares and superflares in the planetary habitability. After an introduction to the topic, in this talk, I am going to show why these theoretical approaches could fail to predict the biological impact of flares and superflares by contrasting these results with those of obtained by our research group where we employ interdisciplinary approaches by combining astrophysical studies with experimental laboratory approaches. Our efforts are part of the “EXO-UV program” and the “Biosun project” international collaborations between astrophysicists, biologists and geologists that seek to expand the biological impact of radiation environments in planetary bodies by using laboratory simulation experiments.