First ZDI with PEPSI

We present a temperature and a magnetic-field surface map of the K2 subgiant of the active binary II Peg. Employed are high resolution Stokes IV spectra obtained with the new Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT). Our main result is that the temperature features on II Peg closely correlate with its magnetic field topology. We find a warm spot (350K warmer with respect to the effective temperature) of positive polarity and radial field density of 1.1 kG coexisting with a cool spot (780K cooler) of negative polarity of 2 kG.

Temperature map from four different viewing angles.

Magnetic field map from four different viewing angles.

Read more: Strassmeier, Carroll & Ilyin http://adsabs.harvard.edu/abs/2019arXiv190211201S

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