Volume 474, Number 1, October IV 2007
|Page(s)||165 - 168|
|Section||Stellar structure and evolution|
|Published online||28 August 2007|
Anti-solar differential rotation on the active K-giant Geminorum
Konkoly Observatory, 1525 Budapest, PO Box 67, Hungary e-mail: email@example.com
2 Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: [jbartus;kstrassmeier]@aip.de
3 Eötvös University, Department of Astronomy, 1518 Budapest, PO Box 32, Hungary e-mail: firstname.lastname@example.org
4 Astronomical Institute, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 18000 Prague 8, Czech Republic e-mail: email@example.com
5 Astronomical Institute, Academy of Sciences of the Czech Republic, v. v. i., Fričova 298, 25165 Ondřejov, Czech Republic
Accepted: 21 July 2007
The active K1 giant σ Gem and its differential surface rotation is revisited. We refine our previous inconclusive result by recovering the spot migration pattern of this long-period RS CVn-type binary through application of the technique of “average cross-correlation of contiguous Doppler images” to a set of six Doppler images from 3.6 consecutive rotation cycles. We find an anti-solar differential rotation law with a shear of -0.022±0.006. We also find evidence of a poleward migration trend of spots with an average velocity of ≈300 m s-1.
Key words: stars: activity / stars: imaging / stars: late-type / stars: starspots / stars: individual: σ Geminorum
© ESO, 2007
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