Physikalisches Kolloquium: Dr. Konstantin Herbst (Institut für Experimentelle und Angewandte Physik, CAU Kiel)

"Exploring the radiation and particle environment of G-, K-, and M-dwarf stars and their impact on (exo)planetary habitability"

09.04.2019 ab 16:15

Leibnizstr. 13, 24118 Kiel, Hans-Geiger Hörsaal

Abstract

 

The search for life outside our solar system was, and still is, a significant motivator for the detection
of extrasolar planets in the Habitable Zone (HZ) of other stellar systems. Since the first confirma-
tion of an exoplanet orbiting a Sun-like (G-type) star in 1995, the existence of thousands of ex-
oplanets has been confirmed, of which well over a dozen were detected within the HZ of their host
stars. With upcoming missions like the James Webb Space Telescope (JWST), the European Ex-
tremely Large Telescope (E-ELT) and the Atmospheric Remote‐ sensing Infrared Exoplanet
Large‐ survey (ARIEL) we soon will be on the verge to detect and characterize atmospheres of,
i.e., rocky Earth-like exoplanets for the first time. Due to their much better detection probability,
thereby, G-, K-, and M-dwarf stars are favored targets of upcoming missions.
However, recent observations showed that the exoplanetary radiation environment around G-, K-,
and M-dwarf stars is much harsher compared to what we know from the Sun. Being located at small
separation to its host star the Earth-like exoplanet is exposed to an enhanced stellar radiation envi-
ronment, which could affect the habitability, e.g., in the form of a hazardous flux of energetic parti-
cles. Knowing the stellar radiation environment, and thus, being able to model the radiation expo-
sure on the surface of a planet is crucial in order to assess its habitability.
Of course, the only planetary system we can study in great detail is our own, the solar system. This
talk will give an overview of what we know about the Sun and its impact on the planets of the solar
system (i.e., Venus, Mars, and Earth), and how this knowledge can be used to determine the particle
and radiation environment of G-, K-, and M-stars. Moreover, to investigate the impact of an active
star on a potential planet in its HZ, we show our model efforts for the nearest stellar neighbor Prox-
ima Centauri and its Earth-like exoplanet Proxima Centauri b.

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