Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Study of the B-V Colour Temperature Relation   We attempt to construct a B-V colour temperature relation for stars in the
least model dependent way employing the best modern data. The fit we obtained
with the form Teff = Teff((B-V)0,[Fe/H],log g) is well constrained and a number
of tests show the consistency of the procedures for the fit. Our relation
covers from F0 to K5 stars with metallicity [Fe/H] = -1.5 to +0.3 for both
dwarfs and giants. The residual of the fit is 66 K, which is consistent with
what are expected from the quality of the present data. Metallicity and surface
gravity effects are well separated from the colour dependence. Dwarfs and
giants match well in a single family of fit, differing only in log g. The fit
also detects the Galactic extinction correction for nearby stars with the
amount E(B-V) = 0.26 +/-0.03 mag/kpc. Taking the newly obtained relation as a
reference we examine a number of B-V colour temperature relations and
atmosphere models available in the literature. We show the presence of a
systematic error in the colour temperature relation from synthetic calculations
of model atmospheres; the systematic error across K0 to K5 dwarfs is 0.04-0.05
mag in B-V, which means 0.25-0.3 mag in Mv for the K star range. We also argue
for the error in the temperature scale used in currently popular stellar
population synthesis models; synthetic colours from these models are somewhat
too blue for aged elliptical galaxies. We derive the colour index of the sun
(B-V)sun = 0.627 +/-0.018, and discuss that redder colours (e.g., 0.66-0.67)
often quoted in the literature are incompatible with the colour-temperature
relation.

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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat