Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A unique hot Jupiter spectral sequence with evidence for compositional
  diversity   The emergent spectra of close-in, giant exoplanets ("hot Jupiters") are
expected to be distinct from those of self-luminous objects with similar
effective temperatures because hot Jupiters are primarily heated from above by
their host stars rather than internally from the release of energy from their
formation. Theoretical models predict a continuum of dayside spectra for hot
Jupiters as a function of irradiation level, with the coolest planets having
absorption features in their spectra, intermediate-temperature planets having
emission features due to thermal inversions, and the hottest planets having
blackbody-like spectra due to molecular dissociation and continuum opacity from
the H- ion. Absorption and emission features have been detected in the spectra
of a number of individual hot Jupiters, and population-level trends have been
observed in photometric measurements. However, there has been no unified,
population-level study of the thermal emission spectra of hot Jupiters such as
has been done for cooler brown dwarfs and transmission spectra of hot Jupiters.
Here we show that hot Jupiter secondary eclipse spectra centered around a water
absorption band at 1.4 microns follow a common trend in water feature strength
with temperature. The observed trend is broadly consistent with model
predictions for how the thermal structures of solar-composition planets vary
with irradiation level. Nevertheless, the ensemble of planets exhibits some
degree of scatter around the mean trend for solar composition planets. The
spread can be accounted for if the planets have modest variations in
metallicity and/or elemental abundance ratios, which is expected from planet
formation models. (abridged abstract)

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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph