Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chromospheres in Metal-Poor Stars Evidenced from the He I 10830A Line   Based on the near-IR spectra of 33 late-type stars in the wide metallicity
range (mainly dwarfs and partly giants) obtained with IRCS+AO188 of the Subaru
Telescope, we confirmed that He I 10830A line is seen in absorption in almost
all moderately to extremely metal-poor stars of thick disk and halo population
(from [Fe/H]~ -0.5 down to [Fe/H]~ -3.7), the strength of which is almost
constant irrespective of the metallicity. This is an evidence that
chromospheric activity at a basal level persists even for such old stars,
despite that their rotations are considered to be slowed down and incapable of
sustaining a dynamo, suggesting that some kind of chromospheric heating
mechanism independent of rotation/magnetism (e.g., acoustic heating) may take
place.

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The categories of this paper are: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg