Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Long-term photometric variability and spectroscopic study of luminous
  blue variable AF And in M31   We present photometric and spectroscopic analysis of the Hubble Sandage
variable AF And in M31. The data has been taken under the Nainital Microlensing
Survey during 1998-2002 and follow-up observations were carried out until 2011.
During this period, photometric observations in Cousins R and I bands were
obtained for 169 nights spanning over about 5000 days. AF And has shown a
prominent outburst around mid-January in 1999 followed by a gradual decrease in
brightness of about 1.5 mag in the next 3 years with a declining rate of
~0.0015 mag/day leading to a quiescent phase at the end of 2001. After lying
low for about 9 years, AF And again went through a secondary outburst phase in
late 2010 with an amplitude of 0.44 mag where it lasted for one year before
fading back to its quiescence phase. The spectroscopic observations of AF And
show prominent Balmer and He I emission lines along with the comparatively
weaker FeII and [FeII] emissions. Asymmetric emission line profiles in its
spectrum imply the mass loss rate of about 2.2x10^{-4} solar mass per yr
through the stellar winds in the photosphere. Using SED fitting, we find the
photospheric temperature of 33,000+/-3000 K during the visual minimum. Using a
weak P Cygni profile of HeI emission line, the wind terminal velocity for AF
And is found to be around 280-300 km/s.

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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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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: funct-an
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ