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arXiv · 0711.0771

Surface velocity network with anti-solar differential rotation on the active K-giant $σ$ Geminorum

Zs. Kõvári·J. Bartus·M. Švanda·K. Vida·K. G. Strassmeier·K. Oláh·E. Forgács-Dajka
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Abstract

We demonstrate the power of the local correlation tracking technique on stellar data for the first time. We recover the spot migration pattern of the long-period RS CVn-type binary $σ$ Gem from a set of six Doppler images from 3.6 consecutive rotation cycles. The resulting surface flow map suggests a weak anti-solar differential rotation with $α\approx-0.0022\pm0.0016$, and a coherent poleward spot migration with an average velocity of $220\pm10$ m s$^{-1}$. This result agrees with our recent findings from another study and could also be confirmed theoretically.

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Zs. Kõvári, J. Bartus, M. Švanda, K. Vida, K. G. Strassmeier, K. Oláh, E. Forgács-Dajka. 2007-11-05. Surface velocity network with anti-solar differential rotation on the active K-giant $σ$ Geminorum. https://doi.org/10.1002/asna.200710874

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