Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 13 Years of P Cygni Spectropolarimetry: Investigating Mass-loss Through
  H$\alpha$, Periodicity, and Ellipticity   We report on over 13 years of optical and near-ultraviolet
spectropolarimetric observations of the famous Luminous Blue Variable (LBV), P
Cygni. LBVs are a critical transitional phase in the lives of the most massive
stars, and achieve the largest mass-loss rates of any group of stars. Using
spectropolarimetry, we are able to learn about the geometry of the near
circumstellar environment surrounding P Cygni and gain insights into LBV
mass-loss. Using data from the HPOL and WUPPE spectropolarimeters, we estimate
the interstellar polarization contribution to P Cygni's spectropolarimetric
signal, analyze the variability of the polarization across the H$\alpha$
emission line, search for periodic signals in the data, and introduce a
statistical method to search for preferred position angles in deviations from
spherical symmetry which is novel to astronomy. Our data are consistent with
previous findings, showing free-electron scattering off of clumps uniformly
distributed around the star. This is complicated, however, by structure in the
percent-polarization of the H$\alpha$ line and a series of previously
undetected periodicities.

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The categories of this paper are: math
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The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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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: cs
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The categories of this paper are: atom-ph
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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: comp-gas