Fear the Shadows of the Giants: On Secular Perturbations in Circumstellar Habitable Zones of Double Stars. (arXiv:2008.11651v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bazso_A/0/1/0/all/0/1">Ákos Bazsó</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pilat_Lohinger_E/0/1/0/all/0/1">Elke Pilat-Lohinger</a>
After the detection of extrasolar planets in binary and multiple star systems
questions arose about their dynamics and habitability. In this study we
investigate a five-dimensional parameter space for wide binary stars with a
massive planet beyond the habitable zone (HZ). Our aim is to reveal those
orbital and physical parameter combinations that expose bodies in the primary
star’s HZ to secular perturbations. Building upon an established
semi-analytical model, we combine two separate analytical models into a new one
to treat the restricted four-body problem. We apply this new Combined
Analytical Model (CAM) to different synthetic systems and systematically map
the occurrence of secular resonances (SR). These maps are then visualized as
two-dimensional sections of the parameter space. The CAM model has a median
error below 3% relative to numerical reference simulations. We also derive a
simplified CAM that performs well for hierarchical systems with moderate to
large separations between the bodies. Our results show that SR appear in the HZ
even for large secondary star distances (up to >1000 au) if either (i) the
planet’s distance is larger than Jupiter’s, or (ii) its mass is about Saturn’s
or lower. Changes in the secondary star’s eccentricity by stellar flybys or
galactic tides can push a formerly dynamically quiet HZ to a high-eccentricity
state. Based on these results we provide the easy-to-use online tool “SHaDoS”
that evaluates the CAM for a given user input and traces the locations of SR in
the HZ in two-dimensional parameter space plots.
After the detection of extrasolar planets in binary and multiple star systems
questions arose about their dynamics and habitability. In this study we
investigate a five-dimensional parameter space for wide binary stars with a
massive planet beyond the habitable zone (HZ). Our aim is to reveal those
orbital and physical parameter combinations that expose bodies in the primary
star’s HZ to secular perturbations. Building upon an established
semi-analytical model, we combine two separate analytical models into a new one
to treat the restricted four-body problem. We apply this new Combined
Analytical Model (CAM) to different synthetic systems and systematically map
the occurrence of secular resonances (SR). These maps are then visualized as
two-dimensional sections of the parameter space. The CAM model has a median
error below 3% relative to numerical reference simulations. We also derive a
simplified CAM that performs well for hierarchical systems with moderate to
large separations between the bodies. Our results show that SR appear in the HZ
even for large secondary star distances (up to >1000 au) if either (i) the
planet’s distance is larger than Jupiter’s, or (ii) its mass is about Saturn’s
or lower. Changes in the secondary star’s eccentricity by stellar flybys or
galactic tides can push a formerly dynamically quiet HZ to a high-eccentricity
state. Based on these results we provide the easy-to-use online tool “SHaDoS”
that evaluates the CAM for a given user input and traces the locations of SR in
the HZ in two-dimensional parameter space plots.
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