Berlin 2014 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 6: Exoplaneten und Astrobiologie
EP 6.5: Vortrag
Donnerstag, 20. März 2014, 11:30–11:45, DO24 1.103
Effects of stellar cosmic ray flux on Earth-like exoplanets around M dwarfs — •Fachreddin Tabataba-Vakili1,2, John Lee Grenfell2,3, Jean-Mathias Grießmeier4,5, and Heike Rauer2,3 — 1University of Oxford, UK — 2TU Berlin, Germany — 3DLR, Berlin, Germany — 4LPC2E, Université d’Orléans, France — 5Station de Radioastronomie de Nancay, France
M-dwarfs are generally considered favorable for rocky planet detection. However, such planets may be subject to extreme conditions due to possible high stellar activity and tidal effects.
The goal of this work is to determine the potential effect of stellar cosmic rays (CR) on key atmospheric species of Earth-like planets orbiting in the HZ of M-dwarf stars and show corresponding changes in the planetary spectra. We improve the CR model scheme of Grenfell et al. (2012), who considered CR-induced NOx production, thereby adding further CR-induced production mechanisms (e.g. HOx) and introducing primary protons of a wider energy range (16 MeV - 0.5 TeV).
Previous studies suggested HZ planets with high atmospheric methane and that the ozone biosignature is destroyed for strong flaring conditions. Our current study shows, however, that adding a new, CR-induced HOx production can cause a decrease in atmospheric methane of up to 80%. Another important result is that spectral signals of ozone remain visible in the theoretical spectrum when incorporating the new CR-induced NOx and HOx schemes, even for a constantly flaring M-star case.