Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical Transmission Spectroscopy of the Terrestrial Exoplanet LHS 3844b
  from 13 Ground-Based Transit Observations   Atmospheric studies of spectroscopically accessible terrestrial exoplanets
lay the groundwork for comparative planetology between these worlds and the
Solar System terrestrial planets. LHS 3844b is a highly-irradiated terrestrial
exoplanet (R=1.303+/-0.022R_Earth) orbiting a mid-M dwarf 15 parsecs away. Work
based on near-infrared Spitzer phase curves ruled out atmospheres with surface
pressures >/=10 bars on this planet. We present 13 transit observations of LHS
3844b taken with the Magellan Clay telescope and the LDSS3C multi-object
spectrograph covering 620-1020 nm. We analyze each of the 13 data sets
individually using a Gaussian process regression, and present both white and
spectroscopic light curves. In the combined white light curve we achieve an RMS
precision of 65 ppm when binning to 10-minutes. The mean white light curve
value of (Rp/Rs)^2 is 0.4170+/-0.0046%. To construct the transmission spectrum,
we split the white light curves into 20 spectrophotometric bands, each spanning
20 nm, and compute the mean values of (Rp/Rs)^2 in each band. We compare the
transmission spectrum to two sets of atmospheric models. We disfavor a clear,
solar composition atmosphere (mu=2.34) with surface pressures >/=0.1 bar to
5.2-sigma confidence. We disfavor a clear, H2O steam atmosphere (mu=18) with
surface pressures >/=0.1 bar to low confidence (2.9-sigma). Our observed
transmission spectrum favors a flat line. For solar composition atmospheres
with surface pressures >/=1 bar we rule out clouds with cloud-top pressures of
0.1 bar (5.3-sigma), but we cannot address high-altitude clouds at lower
pressures. Our results add further evidence that LHS 3844b is devoid of an
atmosphere.

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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
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The categories of this paper are: cs
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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: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn