Planetary Evaporation in 3D: Mechanisms and Consequences. AMR Radiation-Hydrodynamic Simulations of Photoionized Planetary Winds

We present a suite of new, high-resolution 3-D studies of planetary winds driven by host-star ionizing flux.  Using adaptive mesh refinement MHD codes our simulations self-consistently launch the planetary winds by tracking the time-dependent deposition of stellar ionizing radiation into the planet’s atmosphere.  Exploiting the AMR capacities of the code we track the large-scale flow of the planetary wind out to global “star + planet” scales.   Our models include stellar radiation pressure and local ionization dynamics allowing us to track explicitly where in the flow neutrals can be accelerated.  We also include charge-exchange allowing us to follow the development of high-speed flow components.  We present results from a suite of studies that build off our initial, global simulations that explicated the mechanisms forming characteristic up-orbit and down-orbit arms in planetary wind flows (Carroll-Nellenback et al 2017).  Our new work includes an exploration of planet mass and stellar flux on the resulting large scale flows, including the effect on potentially observable neutral trails forming behind the planets.  We also show the relative balance of radiation pressure vs. coriolis forces in determining the large-scale flow patterns.   In addition we present a study of Kepler-12b showing the conditions under which the up/down orbit arms can become a circumstellar torus dense enough to explain the lack of Mg II lines in that system.  Observational consequences for all our studies will be presented via the synthetic observation pipeline we’ve constructed for the simulations.  We conclude with future directions via MHD simulations of planetary wind launching.

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