Spot patterns and differential rotation in the eclipsing pre-cataclysmic variable binary, V471 Tau |
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| Authors: | G A J Hussain C Allende Prieto S H Saar M Still |
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| Institution: | School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS;Astrophysics Division, Research and Science Support Department of ESA, ESTEC, Postbus 299, Noordwijk, the Netherlands;McDonald Observatory and Department of Astronomy, University of Texas, Austin, TX 78712, USA;Harvard Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA;South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape Town, South Africa |
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| Abstract: | We present surface spot maps of the K2V primary star in the pre-cataclysmic variable binary system, V471 Tau. The spot maps show the presence of large high-latitude spots located at the sub-white dwarf longitude region. By tracking the relative movement of spot groups over the course of four nights (eight rotation cycles), we measure the surface differential rotation rate of the system. Our results reveal that the star is rotating rigidly with a surface shear rate, dΩ= 1.6 ± 6 mrad d?1 . The single active star AB Dor has a similar spectral type, rotation period and activity level as the K star in V471 Tau, but displays much stronger surface shear (46 < dΩ < 58 mrad d?1) . Our results suggest that tidal locking may inhibit differential rotation; this reduced shear, however, does not affect the overall magnetic activity levels in active K dwarfs. |
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| Keywords: | binaries: eclipsing stars: imaging stars: individual: V471 Tau stars: late-type stars: magnetic fields stars: spots |
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