Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic field and convection in the cool supergiant Betelgeuse   We present the outcome of a highly-sensitive search for magnetic fields on
the cool supergiant Betelgeuse. A time-series of six circularly-polarized
spectra was obtained using the NARVAL spectropolarimeter at T\'elescope Bernard
Lyot (Pic du Midi Observatory), between 2010 March and April. Zeeman signatures
were repeatedly detected in cross-correlation profiles, corresponding to a
longitudinal component of about 1 G. The time-series unveils a smooth increase
of the longitudinal field from 0.5 to 1.5 G, correlated with radial velocity
fluctuations. We observe a strong asymmetry of Stokes V signatures, also
varying in correlation with the radial velocity. The Stokes V line profiles are
red-shifted by about 9 km/s with respect to the Stokes I profiles, suggesting
that the observed magnetic elements may be concentrated in the sinking
components of the convective flows.

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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: cs
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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: atom-ph
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The categories of this paper are: nucl-ex