Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ULTRACAM photometry of the eclipsing cataclysmic variable OU Vir   We present high-speed, three-colour photometry of the faint eclipsing
cataclysmic variable OU Vir. For the first time in OU Vir, separate eclipses of
the white dwarf and bright spot have been observed. We use timings of these
eclipses to derive a purely photometric model of the system, obtaining a mass
ratio of q = 0.175 +/- 0.025, an inclination of i = 79.2 +/- 0.7 degrees and a
disc radius of Rd/a = 0.2315 +/- 0.0150. We separate the white dwarf eclipse
from the lightcurve and, by fitting a blackbody spectrum to its flux in each
passband, obtain a white dwarf temperature of T = 21700 +/- 1200 K and a
distance of D = 650 +/- 210 pc. Assuming that the primary obeys the Nauenberg
(1972) mass-radius relation for white dwarfs and allowing for temperature
effects, we also find a primary mass Mw/Msun = 0.90 +/- 0.19, primary radius
Rw/Rsun = 0.0097 +/- 0.0031 and orbital separation a/Rsun = 0.75 +/- 0.05.

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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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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: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: physics
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The categories of this paper are: nucl-th