Spot patterns and differential rotation in the eclipsing pre-CV binary,V471 Tau

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, dOmega = 1.6 +/- 6 mrad/d. 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 < dOmega < 58 mrad/d). 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.

12 pages, 9 figures, accepted by MNRAS

References in corpus (1)

• The case for a distributed solar dynamo shaped by near-surface shear

Cited by in corpus (5)

• SW Sextantis stars: the dominant population of CVs with orbital periods between 3-4 hours
• Roche tomography of cataclysmic variables - IV. Starspots and slingshot prominences on BV Cen
• Differential rotation on both components of the pre main-sequence binary system HD 155555
• MOST photometry and DDO spectroscopy of the eclipsing (white dwarf + red dwarf) binary V471 Tau
• Imaging the cool stars in the interacting binaries AE Aqr, BV Cen and V426 Oph