RS CVn binary IM Peg – investigation of stellar activity and surface flows

Abstract

Abstract. We have obtained high resolution, high S/N spectra of the RS CVn binary IM Peg using UVES spectrograph at Kueyen 8.2m telescope of ESO VLT. We use Doppler imaging techniques to obtain stellar surface temperature maps from the UVES data. The TempMap code allows us to use surface differential rotation as an input parameter and thus to try to construct the rotation pattern on the stellar surface as part of the inversion process. The UVES observations are combined with spectroscopic observations from another time period obtained at the STELLA observatory. We obtain stellar surface temperature maps also from these spectra. These Doppler images are used to study the magnetic activity and surface differential rotation on IM Peg.

Photometry and spectroscopy of II Peg, IM Peg and UX Ari

“…Herbst (1973) classified it as a spectral type of KI IV-III with strong CaII H and K emission. Also, the primary shows signs of both photospheric and chromospheric activity and has rotational velocity of v sin i = 28 km s −1 (Korhonen et al 2010). IM Peg undergoes light variations up to 0.3 mag in the V band and these variations arise from the rotation modulation associated with inhomogeneous areal surface coverage of starspots (Strassmeier 1997;Padmakar & Pandey 1999).…”