Modeling star-planet interactions in far-out planetary and exoplanetary systems. (arXiv:1812.07767v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Das_S/0/1/0/all/0/1">Srijan Bharati Das</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Basak_A/0/1/0/all/0/1">Arnab Basak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nandy_D/0/1/0/all/0/1">Dibyendu Nandy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vaidya_B/0/1/0/all/0/1">Bhargav Vaidya</a>

The outflowing magnetized wind from a host star shapes planetary and
exoplanetary magnetospheres dictating the extent of its impact. We carry out
three-dimensional (3D) compressible magnetohydrodynamic (MHD) simulations of
the interactions between magnetized stellar winds and planetary magnetospheres
corresponding to a far-out star-planet system, with and without planetary
dipole obliquity. We identify the pathways that lead to the formation of a
dynamical steady-state magnetosphere and find that magnetic reconnection plays
a fundamental role in the process. The magnetic energy density is found to be
greater on the night-side than that on the day-side and the magnetotail is
comparatively more dynamic. Magnetotail reconnection events are seen to
associated with stellar wind plasma injection into the inner magnetosphere. We
further study magnetospheres with extreme tilt angles keeping in perspective
the examples of Uranus and Neptune. High dipole obliquities may also manifest
due to polarity excursions during planetary field reversals. We find that
global magnetospheric reconnection sites change for large planetary dipole
obliquity and more complex current sheet structures are generated. We discuss
the implications of these findings for injection of interplanetary species and
energetic particles into the inner magnetosphere, auroral activity and
magnetospheric radio emission. This study is relevant for exploring star planet
interactions in the solar and extra-solar systems.

The outflowing magnetized wind from a host star shapes planetary and
exoplanetary magnetospheres dictating the extent of its impact. We carry out
three-dimensional (3D) compressible magnetohydrodynamic (MHD) simulations of
the interactions between magnetized stellar winds and planetary magnetospheres
corresponding to a far-out star-planet system, with and without planetary
dipole obliquity. We identify the pathways that lead to the formation of a
dynamical steady-state magnetosphere and find that magnetic reconnection plays
a fundamental role in the process. The magnetic energy density is found to be
greater on the night-side than that on the day-side and the magnetotail is
comparatively more dynamic. Magnetotail reconnection events are seen to
associated with stellar wind plasma injection into the inner magnetosphere. We
further study magnetospheres with extreme tilt angles keeping in perspective
the examples of Uranus and Neptune. High dipole obliquities may also manifest
due to polarity excursions during planetary field reversals. We find that
global magnetospheric reconnection sites change for large planetary dipole
obliquity and more complex current sheet structures are generated. We discuss
the implications of these findings for injection of interplanetary species and
energetic particles into the inner magnetosphere, auroral activity and
magnetospheric radio emission. This study is relevant for exploring star planet
interactions in the solar and extra-solar systems.

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