Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galactic S Stars: Investigations of Color, Motion, and Spectral Features   Known bright S stars, recognized as such by their enhanced s-process
abundances and C/O ratio, are typically members of the asymptotic giant branch
(AGB) or the red giant branch (RGB). Few modern digital spectra for these
objects have been published, from which intermediate resolution spectral
indices and classifications could be derived. For published S stars we find
accurate positions using the Two-Micron All Sky Survey (2MASS), and use the
FAST spectrograph of the Tillinghast reflector on Mt. Hopkins to obtain the
spectra of 57 objects. We make available a digital S star spectral atlas
consisting of 14 spectra of S stars with diverse spectral features. We define
and derive basic spectral indices that can help distinguish S stars from
late-type (M) giants and carbon stars. We convolve all our spectra with the
SDSS bandpasses, and employ the resulting gri magnitudes together with 2MASS
JHK mags to investigate S star colors. S stars have colors similar to carbon
and M stars, and are therefore difficult to distinguish by color alone. Using
near and mid-infrared colors from IRAS and AKARI, we identify some of the stars
as intrinsic (AGB) or extrinsic (with abundances enhanced by past
mass-transfer). We also use V band and 2MASS magnitudes to calculate a
temperature index for stars in the sample. We analyze the proper motions and
parallaxes of our sample stars to determine upper and lower limit absolute
magnitudes and distances, and confirm that most are probably giants.

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The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: physics
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph