Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Carbon monoxide emission lines reveal an inverted atmosphere in the
  ultra hot Jupiter WASP-33 b and indicate an eastward hot spot   We report the first detection of CO emission lines at high spectral
resolution in the day-side infrared thermal spectrum of an exoplanet. These
emission lines, found in the atmosphere of the ultra hot Jupiter WASP-33 b,
provide unambiguous evidence of its thermal inversion layer. Using spectra from
the MMT Exoplanet Atmosphere Survey (MEASURE, $R\sim15,000$), covering pre- and
post-eclipse orbital phases ($0.33<\phi<0.73$), we performed a
cross-correlation analysis with 1D PHOENIX model atmospheres to detect CO at
S/N=7.9 at $v_{sys}=0.15^{+0.64}_{-0.65}$ km/s and $K_{p}=229.5^{+1.1}_{-1.0}$
km/s. However, using the framework of Cross-Correlation-to-log-Likelihood
mapping, we further find that the spectral line depths, as probed by the
scaling parameter, change with phase: the line contrast is larger after the
eclipse than before. We then use the general circulation model SPARC/MITgcm
post-processed by the 3D gCMCRT radiative transfer code and interpret this
variation as due to an eastward-shifted hot spot. Before the eclipse, when the
hot spot is facing Earth, the thermal profiles are shallower, leading to a
smaller line depth despite greater overall flux. After the eclipse, the western
part of the day-side is facing Earth, where the thermal profiles are much
steeper, leading to larger line depth despite less overall flux. We thus
demonstrate that even relatively moderate resolution spectra can be used to
understand the 3D nature of close-in exoplanets, if assessed within the
log-likelihood framework, and that resolution can be traded for photon
collecting power when the induced Doppler-shift is sufficiently large. We
highlight that CO in ultra hot Jupiters is a good probe of their thermal
structure and corresponding dynamics, and does not suffer from stellar activity
unlike some atomic species, such as iron, that also appear in the hot host star
spectrum.

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The categories of this paper are: hep-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th