Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pulsations and Long-Term Light Variability of Three Candidates to
  Protoplanetary Nebulae   We present new photometric data and analysis of the long-duration UBV
photoelectric observations for three candidates to protoplanetary objects -
F-supergiants with IR-excesses located at large galactic latitudes, IRAS
18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All three stars have revealed
quasiperiodic low-amplitude variabilities caused by pulsations observed against
the long-term trends of brightnesses. For IRAS 18095+2704=V887 Her we have
found a pulsation period of 109 days and a linear trend of brightness under the
constant colours if being averaged over the year timescale. The light curve of
IRAS 19386+0155=V1648 Aql over 2000-2008 can be approximated by a wave with a
main period of 102 days which is modulated by close frequency, with a period of
98 days, that results in brightness oscillations with a variable amplitude.
V1648 Aql has also shown synchronous reddening together with a persistent rise
of brightness in the V-band. IRAS 19500-1709=V5112 Sgr experiences irregular
pulsations with the periods of 39 and 47 days. The long-term component of the
variability of V5112 Sgr may be related to the binary character of this star.

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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga