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

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 نشر من قبل Zsolt K\\H{o}v\\'ari
 تاريخ النشر 2007
  مجال البحث فيزياء
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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 $sigma$ 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 $alphaapprox-0.0022pm0.0016$, and a coherent poleward spot migration with an average velocity of $220pm10$ m s$^{-1}$. This result agrees with our recent findings from another study and could also be confirmed theoretically.



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