Exoplanetary Habitability: Radiation, Particles, Plasmas, and Magnetic Fields
- Author(s)
- Manuel Güdel
- Abstract
Exoplanetary environments are made of an intricate mixture of plasmas, radiation, energetic particles, winds, and magnetic fields; these all play crucial roles for the structure and evolution of planetary atmospheres and the formation and possibly protection of planetary habitable environments. Interactions between planetary atmospheric particles and solar-wind ions result in various non-thermal loss mechanisms that are relevant for atmospheric erosion; energetic neutral atoms from charge exchange interactions can even deposit their energy in upper atmospheres and contribute to their heating. We present results from simulations and discuss the effects of magnetospheric obstacles, the resulting atmospheric loss rates and neutral hydrogen clouds detectable through Ly a absorption. We also present estimates for secondary X-ray production as a result of charge exchange interactions. Combined modeling of expanding hydrogen clouds resulting from such interactions are now also used to estimate magnetic moments of exoplanets. We emphasize that the interplay between all these mechanisms, also including radiation-driven thermal escape of atmospheres, changes with stellar evolution; for a full understanding of the state of an observed exoplanetary atmosphere, the long-term evolution of the host star, in particular its rotation and magnetic activity, needs to be studied. In this respect, radio astronomy plays a central role as it sensitively probes these environments and their constituents in time, such as magnetospheres, high-energy particles, stellar magnetic fields and winds, and therefore contributes to our understanding of the emergence of habitable planetary environments.
- Organisation(s)
- Department of Astrophysics
- Publication date
- 05-2017
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/36165872-e99c-4ad4-a082-20db0b589baf