Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: CCD photometry in the region of NGC 6994: the remains of an old open
  cluster   We present the results of BV(RI)_KC CCD photometry down to V=21 mag in the
region of NGC 6994. To our knowledge, no photometry has previously been
reported for this object and we find evidences that it is a poor and sparse old
open cluster, with a minimum angular diameter of 9 arcmin, i.e. larger than the
3 arcmin originally assigned to it. We obtain a color excess E(B-V) = 0.07 +/-
0.02 mag by means of the BVI_(C) technique. Based on the theoretical isochrones
from VandenBergh (1985) that are in better agreement with our data, we estimate
for this cluster a distance from the Sun of 620 pc (Vo-Mv = 9 +/- 0.25 mag) and
an age lying within the range of 2 - 3 Gyr, adopting solar metallicity. Thus,
the corresponding cluster's Galactocentric distance is 8.1 kpc and is placed at
about 350 pc below the Galactic plane. According to this results, NGC 6994
belongs to the old open cluster population located in the outer disk and at
large distances from the Galactic plane, and must have suffered significant
individual dynamical evolution, resulting in mass segregation and evaporation
of low mass stars.

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The categories of this paper are: cmp-lg
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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: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: q-alg
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: stat
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio