Vol. 561
In section 8. Stellar atmospheres

Search for surface magnetic fields in Mira stars. First detection in chi Cygni

by A. Lèbre, M. Aurière, N. Fabas, D. Gillet, F. Herpin, R. Konstantinova-Antova, and P. Petit, A&A 561, A85


The authors present the first spectropolarimetric observations of the S-type Mira star chi Cyg, performed around its maximum light. They detected a polarimetric signal in the Stokes V spectra and established its Zeeman origin, related to a weak magnetic field present at the photospheric level and in the lower part of the stellar atmosphere. The strength of the longitudinal component is about 2-3 gauss. This is the first detection of a weak magnetic field at the stellar surface of a Mira star.