Doppler imaging of stellar surface structure

XXIV. the lithium-rich single K-giants DP Canum Venaticorum and di Piscium

Z. Kővári, H. Korhonen, K. G. Strassmeier, M. Weber, L. Kriskovics, I. Savanov

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Aims. 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. Methods. Optical spectroscopy and photometry were used to determine the fundamental astrophysical properties. Doppler imaging was applied to recover the surface temperature distribution for both stars, while photometric light-curve inversions were carried out for studying the long-term changes of the surface activity of DP CVn. Surface differential rotation of DP CVn was estimated from cross-correlating the available subsequent Doppler reconstructions separated by roughly one rotation period. Results. 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 ΔT ≈ 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 α =-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.

Original languageEnglish
Article numberA2
JournalAstronomy and Astrophysics
Volume551
DOIs
Publication statusPublished - 2013

Fingerprint

lithium
stars
dredger
long-term change
local thermodynamic equilibrium
surface temperature
tropical regions
polar regions
spectroscopy
light curve
photometry
astrophysics
temperature distribution
inversions
modulation
configurations
temperature

Keywords

  • Stars: activity
  • Stars: imaging
  • Stars: individual: DI Psc
  • Stars: individual: DP CVn
  • Stars: late-type
  • Starspots

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Doppler imaging of stellar surface structure : XXIV. the lithium-rich single K-giants DP Canum Venaticorum and di Piscium. / Kővári, Z.; Korhonen, H.; Strassmeier, K. G.; Weber, M.; Kriskovics, L.; Savanov, I.

In: Astronomy and Astrophysics, Vol. 551, A2, 2013.

Research output: Contribution to journalArticle

Kővári, Z. ; Korhonen, H. ; Strassmeier, K. G. ; Weber, M. ; Kriskovics, L. ; Savanov, I. / Doppler imaging of stellar surface structure : XXIV. the lithium-rich single K-giants DP Canum Venaticorum and di Piscium. In: Astronomy and Astrophysics. 2013 ; Vol. 551.
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