Simplified 3D GCM modelling of the irradiated brown dwarf WD0137-349B. (arXiv:2001.06558v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lee_G/0/1/0/all/0/1">Graham K.H. Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casewell_S/0/1/0/all/0/1">Sarah L. Casewell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chubb_K/0/1/0/all/0/1">Katy L. Chubb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hammond_M/0/1/0/all/0/1">Mark Hammond</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tan_X/0/1/0/all/0/1">Xianyu Tan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsai_S/0/1/0/all/0/1">Shang-Min Tsai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pierrehumbert_R/0/1/0/all/0/1">Raymond T. Pierrehumbert</a>
Context: White dwarf – Brown dwarf short period binaries (P$_{rm orb}$
$lesssim$ 2 hours) are some of the most extreme irradiated atmospheric
environments known. These systems offer an opportunity to explore theoretical
and modelling efforts of irradiated atmospheres different to typical hot
Jupiter systems. Aims: We aim to investigate the three dimensional atmospheric
structural and dynamical properties of the Brown dwarf WD0137-349B. Methods: We
use the three dimensional GCM model Exo-FMS, with a dual-band grey
radiative-transfer scheme to model the atmosphere of WD0137-349B. The results
of the GCM model are post-processed using the three dimensional Monte Carlo
radiative-transfer model CMCRT. Results: Our results suggest inefficient
day-night energy transport and a large day-night temperature contrast for
WD0137-349B. Multiple flow patterns are present, shifting energy asymmetrically
eastward or westward depending on their zonal direction and latitude. Regions
of Hadley-like overturning are produced on the western terminator. We are able
to reproduce the observed start of the systems near-IR emission excess at
$gtrsim$ 1.95 $mu$m. Our model over predicts the IR phase curve fluxes by
factors of $approx$1-3, but generally fits the shape of the phase curves well.
Conclusions: We present a first attempt at simulating the atmosphere of a short
period White dwarf – Brown dwarf binary in a 3D setting. Further studies into
the radiative and photochemical heating from the UV irradiation is required to
more accurately capture the energy balance inside the Brown dwarf atmosphere.
Cloud formation may also play an important role in shaping the emission spectra
of the Brown dwarf.
Context: White dwarf – Brown dwarf short period binaries (P$_{rm orb}$
$lesssim$ 2 hours) are some of the most extreme irradiated atmospheric
environments known. These systems offer an opportunity to explore theoretical
and modelling efforts of irradiated atmospheres different to typical hot
Jupiter systems. Aims: We aim to investigate the three dimensional atmospheric
structural and dynamical properties of the Brown dwarf WD0137-349B. Methods: We
use the three dimensional GCM model Exo-FMS, with a dual-band grey
radiative-transfer scheme to model the atmosphere of WD0137-349B. The results
of the GCM model are post-processed using the three dimensional Monte Carlo
radiative-transfer model CMCRT. Results: Our results suggest inefficient
day-night energy transport and a large day-night temperature contrast for
WD0137-349B. Multiple flow patterns are present, shifting energy asymmetrically
eastward or westward depending on their zonal direction and latitude. Regions
of Hadley-like overturning are produced on the western terminator. We are able
to reproduce the observed start of the systems near-IR emission excess at
$gtrsim$ 1.95 $mu$m. Our model over predicts the IR phase curve fluxes by
factors of $approx$1-3, but generally fits the shape of the phase curves well.
Conclusions: We present a first attempt at simulating the atmosphere of a short
period White dwarf – Brown dwarf binary in a 3D setting. Further studies into
the radiative and photochemical heating from the UV irradiation is required to
more accurately capture the energy balance inside the Brown dwarf atmosphere.
Cloud formation may also play an important role in shaping the emission spectra
of the Brown dwarf.
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