Stellar Influence on Heavy Ion Escape from Unmagnetized Exoplanets. (arXiv:1903.05649v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Egan_H/0/1/0/all/0/1">Hilary Egan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jarvinen_R/0/1/0/all/0/1">Riku Jarvinen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brain_D/0/1/0/all/0/1">David Brain</a>
Planetary habitability is in part determined by the atmospheric evolution of
a planet; one key component of such evolution is escape of heavy ions to space.
Ion loss processes are sensitive to the plasma environment of the planet,
dictated by the stellar wind and stellar radiation. These conditions are likely
to vary from what we observe in our own solar system when considering a planet
in the habitable zone around an M-dwarf. Here we use a hybrid global plasma
model to perform a systematic study of the changing plasma environment and ion
escape as a function of stellar input conditions, which are designed to mimic
those of potentially habitable planets orbiting M-dwarfs. We begin with a
nominal case of a solar wind experienced at Mars today, and incrementally
modify the interplanetary magnetic field orientation and strength, dynamic
pressure, and Extreme Ultraviolet input. We find that both ion loss morphology
and overall rates vary significantly, and in cases where the stellar wind
pressure was increased, the ion loss began to be diffusion or production
limited with roughly half of all produced ions being lost. This limit implies
that extreme care must be taken when extrapolating loss processes observed in
the solar system to extreme environments.
Planetary habitability is in part determined by the atmospheric evolution of
a planet; one key component of such evolution is escape of heavy ions to space.
Ion loss processes are sensitive to the plasma environment of the planet,
dictated by the stellar wind and stellar radiation. These conditions are likely
to vary from what we observe in our own solar system when considering a planet
in the habitable zone around an M-dwarf. Here we use a hybrid global plasma
model to perform a systematic study of the changing plasma environment and ion
escape as a function of stellar input conditions, which are designed to mimic
those of potentially habitable planets orbiting M-dwarfs. We begin with a
nominal case of a solar wind experienced at Mars today, and incrementally
modify the interplanetary magnetic field orientation and strength, dynamic
pressure, and Extreme Ultraviolet input. We find that both ion loss morphology
and overall rates vary significantly, and in cases where the stellar wind
pressure was increased, the ion loss began to be diffusion or production
limited with roughly half of all produced ions being lost. This limit implies
that extreme care must be taken when extrapolating loss processes observed in
the solar system to extreme environments.
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