Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of a weak magnetic field in the photosphere of the single
  giant Pollux   Aims: We observe the nearby, weakly-active single giant, Pollux, in order to
directly study and infer the nature of its magnetic field. Methods: We used the
new generation spectropolarimeters ESPaDOnS and NARVAL to observe and detect
circular polarization within the photospheric absorption lines of Pollux. Our
observations span 18 months from 2007-2009. We treated the spectropolarimetric
data using the Least-Squares Deconvolution method to create high
signal-to-noise ratio mean Stokes V profiles. We also measured the classical
activity indicator S-index for the Ca H&K lines, and the stellar radial
velocity (RV). Results: We have unambiguously detected a weak Stokes V signal
in the spectral lines of Pollux, and measured the related surface-averaged
longitudinal magnetic field Bl. The longitudinal field averaged over the span
of the observations is below one gauss. Our data suggest variations of the
longitudinal magnetic field, but no significant variation of the S-index. We
observe variations of RV which are qualitatively consistent with the published
ephemeris for a proposed exoplanet orbiting Pollux. The observed variations of
Bl appear to mimic those of RV, but additional data for this relationship to be
established. Using evolutionary models including the effects of rotation, we
derive the mass of Pollux and we discuss its evolutionary status and the origin
of its magnetic field. Conclusions: This work presents the first direct
detection of the magnetic field of Pollux, and demonstrates that ESPaDOnS and
NARVAL are capable of obtaining sub-G measurements of the surface-averaged
longitudinal magnetic field of giant stars, and of directly studying the
relationships between magnetic activity, stellar evolution and planet hosting
of these stars.

14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
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The categories of this paper are: eess
9
The categories of this paper are: nlin
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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: dg-ga
30
The categories of this paper are: q-alg