Exoclimes_Conference_booklet1

planet’s dayside, terminator and reflected polarized light are modeled and compared to
available data.
Circumplanetary Jet Formation, Characteristics, and Observational Diagnostics
Ian Dobbs-Dixon — University of Washington!
Ubiquitous among multidimensional simulations of highly irradiated gas-giant planets is the
development of circumplanetary jets in the equatorial region of the planet. These jets,
many of which become supersonic, are the dominant dynamical feature, helping to shape
all observable features and perhaps influencing the thermal evolution of the entire planet.
However, observations of irradiated gas-giants suggest that not all planets form such jets.
Despite their importance for interpreting observations, the precise physical mechanism for
forming and sustaining jets remains an area of active research. We lay out a linear theory
for the formation of these jets and compare our predicted behavior to results from
multidimensional radiative-hydrodynamical simulations. We then further discuss a novel
observational technique for detecting these jets during a single eclipse. A faster method of
detecting a jet will allow for a much broader survey of systems, hopefully shedding light on
the physical parameters of the system that help or hinder jet formation.
Escape of Hydrogen from HD209458b!
Justin!Erwin — University of Arizona!
Recent modeling of the atmosphere of HD209458b has been used to interpret the Lymanline
and other observations during transits. Koskinen et al. (2010) used a hydrostatic
density profile in the thermosphere combined with the Voigt profile to estimate the Lymanalpha
transit depths for an array of model parameters. A detailed photochemical-dynamical
model of the thermosphere was developed by Koskinen et al. (2013a) and used to again
estimate model parameters to fit not only the Lyman-alpha transits, but also the transits in
the O I, C II and Si III lines (Koskinen et al., 2013b). Recently, Bourrier and Lecavelier
(2013) modeled the escape of hydrogen from the extended atmospheres of HD209458b
and HD189733b and used the results to interpret Lyman-alpha observations. They
included acceleration of hydrogen by radiation pressure and stellar wind protons to
simulate the high velocity tails of the velocity distribution, arguing that the observations are
explained by high velocity gas in the system while Voigt broadening is negligible.
In this work we connect a free molecular flow (FMF) model similar to Bourrier and
Lecavelier (2013) to the results of Koskinen et al. (2013b) and properly include absorption
by the extended thermosphere in the transit model. In this manner, we can interpret the
necessity of the various physical processes in matching the observed line profiles.
Furthermore, the transit depths of this model can be used to re-evaluate the atmospheric
model parameters to determine if they need to be adjusted due to the existence of the
extended hydrogen tail.
Thor: A GPU code for simulating exoplanetry atmospheres
Simon!Grimm — University of Zürich
We present an implementation of a three-dimensional general circulation model (GSM),
designed for simulating exoplanetary atmospheres, running fully parallel on Graphics
Processing Units (GPU’s). The Code is developed for the Exoclimes Simulation Platform
(ESP) and will be available as open source software. Thor solves the three dimensional
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