Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectropolarimetric signatures of Earth-like extrasolar planets   We present results of numerical simulations of the flux (irradiance), F, and
the degree of polarization (i.e. the ratio of polarized to total flux), P, of
light that is reflected by Earth-like extrasolar planets orbiting solar-type
stars, as functions of the wavelength (from 0.3 to 1.0 micron, with 0.001
micron spectral resolution) and as functions of the planetary phase angle. We
use different surface coverages for our model planets, including vegetation and
a Fresnel reflecting ocean, and clear and cloudy atmospheres. Our
adding-doubling radiative transfer algorithm, which fully includes multiple
scattering and polarization, handles horizontally homogeneous planets only; we
simulate fluxes and polarization of horizontally inhomogeneous planets by
weighting results for homogeneous planets. Like the flux, F, the degree of
polarization, P, of the reflected starlight is shown to depend strongly on the
phase angle, on the composition and structure of the planetary atmosphere, on
the reflective properties of the underlying surface, and on the wavelength, in
particular in wavelength regions with gaseous absorption bands. The sensitivity
of P to a planet's physical properties appears to be different than that of F.
Combining flux with polarization observations thus makes for a strong tool for
characterizing extrasolar planets. The calculated total and polarized fluxes
will be made available through the CDS.

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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th