Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Further constraints on the optical transmission spectrum of HAT-P-1b   We report on novel observations of HAT-P-1 aimed at constraining the optical
transmission spectrum of the atmosphere of its transiting Hot-Jupiter
exoplanet. Ground-based differential spectrophotometry was performed over two
transit windows using the DOLORES spectrograph at the Telescopio Nazionale
Galileo (TNG). Our measurements imply an average planet to star radius ratio
equal to $\rm R_p/R_{\star}$=(0.1159$\pm$0.0005). This result is consistent
with the value obtained from recent near infrared measurements of this object
but differs from previously reported optical measurements being lower by around
4.4 exoplanet scale heights. Analyzing the data over 5 different spectral bins
600\AA$\,$ wide we observed a single peaked spectrum (3.7 $\rm\sigma$ level)
with a blue cut-off corresponding to the blue edge of the broad absorption wing
of sodium and an increased absorption in the region in between 6180-7400\AA. We
also infer that the width of the broad absorption wings due to alkali metals is
likely narrower than the one implied by solar abundance clear atmospheric
models. We interpret the result as evidence that HAT-P-1b has a partially clear
atmosphere at optical wavelengths with a more modest contribution from an
optical absorber than previously reported.

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The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th