Differential rotation on UZ librae

K. Oláh, J. Jurcsik, K. G. Strassmeier

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We analysed a time series of nine consecutive years of high-precision photometry of the spotted RS CVn stars UZ Lib by using a discrete Fourier-transform technique and a non-linear least-squares minimization. The main period of 4.77 days due to stellar rotation was resolved into three individual periods separated by -0.2% and +0.4% around the main period. The stability of the spot pattern over many years, as derived from our contemporaneous Doppler images, allowed us to relate the different periods to co-existing spots at different latitudes, and thus to the direct determination of the strength and the sign of the differential rotation. The main period originates from the equatorial surface regions and is practically the same as the orbital period from independent radial-velocity measurements, suggesting that the stellar equator is tidally locked to the orbital motion. The higher latitudes rotate slightly faster than the equator, suggesting non-solar differential rotation with a parameter of α = ΔΩ/Ω = -0.0026, 80 times weaker than on the solar surface, and a lap time of Pequator/α ≈ -1800 days, i.e. 14 times longer than for the Sun.

Original languageEnglish
Pages (from-to)685-689
Number of pages5
JournalAstronomy and Astrophysics
Volume410
Issue number2
DOIs
Publication statusPublished - Nov 2003

Fingerprint

equators
stellar rotation
velocity measurement
radial velocity
polar regions
photometry
orbits
stars
orbitals
Fourier transform
optimization
time series

Keywords

  • Stars: activity
  • Stars: atmospheres
  • Stars: binaries: close
  • Stars: individual: UZ Lib
  • Stars: late-type
  • Starspots

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Differential rotation on UZ librae. / Oláh, K.; Jurcsik, J.; Strassmeier, K. G.

In: Astronomy and Astrophysics, Vol. 410, No. 2, 11.2003, p. 685-689.

Research output: Contribution to journalArticle

Oláh, K. ; Jurcsik, J. ; Strassmeier, K. G. / Differential rotation on UZ librae. In: Astronomy and Astrophysics. 2003 ; Vol. 410, No. 2. pp. 685-689.
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