Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical photometry and basic parameters of 10 unstudied open clusters   We present BVI CCD photometry of 10 northern open clusters, Berkeley 43,
Berkeley 45, Berkeley 47, NGC 6846, Berkeley 49, Berkeley 51, Berkeley 89,
Berkeley 91, Tombaugh 4 and Berkeley 9, and estimate their fundamental
parameters. Eight of the clusters are located in the first galactic quadrant
and 2 are in the second. This is the first optical photometry for 8 clusters.
All of them are embedded in rich galactic fields and have large reddening
towards them (E(B-V) = 1.0 - 2.3 mag). There is a possibility that some of
these difficult-to-study clusters may be asterisms rather than physical
systems, but assuming they are physical clusters, we find that 8 of them are
located beyond 2 kpc, and 6 clusters (60% of the sample) are located well above
or below the Galactic plane. Seven clusters have ages 500 Myr or less and the
other 3 are 1 Gyr or more in age. This sample of clusters has increased the
optical photometry of clusters in the second half of the first galactic
quadrant, beyond 2 kpc, from 10 to 15. NGC 6846 is found to be one of the most
distant clusters in this region of the Galaxy.

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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: physics
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The categories of this paper are: q-bio