Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stellar activity analysis of Barnard's Star: Very slow rotation and
  evidence for long-term activity cycle   The search for Earth-like planets around late-type stars using ultra-stable
spectrographs requires a very precise characterization of the stellar activity
and the magnetic cycle of the star, since these phenomena induce radial
velocity (RV) signals that can be misinterpreted as planetary signals. Among
the nearby stars, we have selected Barnard's Star (Gl 699) to carry out a
characterization of these phenomena using a set of spectroscopic data that
covers about 14.5 years and comes from seven different spectrographs: HARPS,
HARPS-N, CARMENES, HIRES, UVES, APF, and PFS; and a set of photometric data
that covers about 15.1 years and comes from four different photometric sources:
ASAS, FCAPT-RCT, AAVSO, and SNO. We have measured different chromospheric
activity indicators (H$\alpha$, Ca~{\sc II}~HK and Na I D), as well as the FWHM
of the cross-correlation function computed for a sub-set of the spectroscopic
data. The analysis of Generalized Lomb-Scargle periodograms of the time series
of different activity indicators reveals that the rotation period of the star
is 145 $\pm$ 15 days, consistent with the expected rotation period according to
the low activity level of the star and previous claims. The upper limit of the
predicted activity-induced RV signal corresponding to this rotation period is
about 1 m/s. We also find evidence of a long-term cycle of 10 $\pm$ 2 years
that is consistent with previous estimates of magnetic cycles from photometric
time series in other M stars of similar activity levels. The available
photometric data of the star also support the detection of both the long-term
and the rotation signals.

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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: ao-sci