Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The CARMENES search for exoplanets around M dwarfs. Chromospheric
  modeling of M2-3 V stars with PHOENIX   Chromospheric modeling of observed differences in stellar activity lines is
imperative to fully understand the upper atmospheres of late-type stars. We
present one-dimensional parametrized chromosphere models computed with the
atmosphere code PHOENIX using an underlying photosphere of 3500 K. The aim of
this work is to model chromospheric lines of a sample of 50 M2-3 dwarfs
observed in the framework of the CARMENES, the Calar Alto high-Resolution
search for M dwarfs with Exo-earths with Near-infrared and optical Echelle
Spectrographs, exoplanet survey. The spectral comparison between observed data
and models is performed in the chromospheric lines of Na I D2, H$\alpha$, and
the bluest Ca II infrared triplet line to obtain best-fit models for each star
in the sample. We find that for inactive stars a single model with a VAL C-like
temperature structure is sufficient to describe simultaneously all three lines
adequately. Active stars are rather modeled by a combination of an inactive and
an active model, also giving the filling factors of inactive and active
regions. Moreover, the fitting of linear combinations on variable stars yields
relationships between filling factors and activity states, indicating that more
active phases are coupled to a larger portion of active regions on the surface
of the star.

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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: hep-ph
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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: cs
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The categories of this paper are: chao-dyn
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The categories of this paper are: physics
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The categories of this paper are: math
8
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: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat