Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Doppler imaging of stellar surface structure - XXIV. The lithium-rich
  single K-giants DP Canum Venaticorum and DI Piscium   We present the first Doppler imaging study of the two rapidly rotating,
single K-giants DP CVn and DI Psc in order to study the surface spot
configuration and to pinpoint their stellar evolutionary status. Optical
spectroscopy and photometry are used to determine the fundamental astrophysical
properties. Doppler imaging is applied to recover the surface temperature
distribution for both stars, while photometric light-curve inversions are
carried out for studying the long-term changes of the surface activity of DP
CVn. Surface differential rotation of DP CVn is estimated from
cross-correlating the available subsequent Doppler reconstructions separated by
roughly one rotation period. Both stars appear to have higher than normal
lithium abundance, LTE log n of 2.28 (DP CVn) and 2.20 (DI Psc), and are
supposed to be located at the end of the first Li dredge-up on the RGB.
Photometric observations reveal rotational modulation with a period of 14.010 d
(DP CVn) and 18.066 d (DI Psc). Doppler reconstructions from the available
mapping lines well agree in the revealed spot patterns, recovering rather low
latitude spots for both stars with temperature contrasts of Delta T ~ 600-800 K
below the unspotted photospheric background. Spots at higher latitudes are also
found but either with less contrast (DP CVn) or with smaller extent (DI Psc). A
preliminary antisolar-type differential rotation with alpha=-0.035 is found for
DP CVn from cross-correlating the subsequent Doppler images. Long-term
photometric analysis supports the existence of active longitudes, as well as
the differential rotation.

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The categories of this paper are: math
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: cs