The first Doppler imaging of the active binary prototype RS Canum Venaticorum

Abstract

We present the first Doppler images of the prototypical active binary star RS CVn, derived from high-resolution spectra observed in 2004, 2016 and 2017, using three different telescopes and observing sites. We apply the least-squares deconvolution technique to all observed spectra to obtain high signal-to-noise line profiles, which are used to derive the surface images of the active K-type component. Our images show a complex spot pattern on the K star, distributed widely in longitude. All starspots revealed by our Doppler images are located below a latitude of about 70${}^{\circ }$. In accordance with previous light-curve modeling studies, we find no indication of a polar spot on the K star. Using Doppler images derived from two consecutive rotational cycles, we estimate a surface differential rotation rate of $\Delta \Omega =-0.039\pm 0.003rad{d}^{-1}$ and $\alpha =\Delta \Omega /{\Omega }_{eq}=-0.030\pm 0.002$ for the K star. Given the limited phase coverage during those two rotations, the uncertainty of our differential rotation estimate is presumably higher.

11 pages, 10 figures, accepted for publication in MNRAS

References in corpus (12)

• The Gaia mission
• On differential rotation and overshooting in solar-like stars
• Magnetic flux transport on active cool stars and starspot lifetimes
• The impact of meridional circulation on stellar butterfly diagrams and polar caps
• Long-term magnetic activity in close binary systems. I. Patterns of color variations
• Differential rotation on both components of the pre main-sequence binary system HD 155555
• Antisolar differential rotation of the K1-giant sigma Geminorum revisited
• Rotation--differential rotation relationships for late-type single and binary stars from Doppler imaging
• Anti-solar differential rotation on the active sub-giant HU Virginis
• Time-series Doppler imaging of the red giant HD 208472. Active longitudes and differential rotation
• Lithium enrichment on the single active K1-giant DI Piscium -- Possible joint origin of differential rotation and Li enrichment
• Doppler images of the eclipsing binary ER Vulpeculae