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The young active G-dwarf star V889 Herculis (HD 171488) shows pronouncedspots in Doppler images as well as large variations in photometry and radialvelocity (RV) measurements. However, the lifetime and evolution of its activeregions are not well known. We study the existence and stability of activeregions on the star's surface using complementary data and methods.Furthermore, we analyze the correlation of spot-induced RV variations andDoppler images. Photometry and high-resolution spectroscopy are used to examinestellar activity. A CLEAN-like Doppler Imaging (DI) algorithm is used to derivesurface reconstructions. We study high-precision RV curves to determine theirmodulation due to stellar activity in analogy to the Rossiter-McLaughlineffect. To this end we develop a measure for the shift of a line's center andcompare it to RV measurements. We show that large spotted regions exist on V889Her for more than one year remaining similar in their large scale structure andposition. This applies to several time periods of our observations, which covermore than a decade. Furthermore we use DI line profile reconstructions toidentify influences of long-lasting starspots on RV measurements. In this waywe verify the RV curve's agreement with our Doppler images. Based on long-termRV data we confirm V889 Her's rotation period of $1.3371 \pm 0.0002$ days.

astronomy and astrophysics

Long-term stability of spotted regions and the activity-induced  Rossiter-McLaughlin effect on V889 Herculis. A synergy of photometry, radial  velocity measurements, and Doppler imaging