Abstract:
The intimate association between the surface magnetic fields and the Ca II K-line emission known to exist on the Sun, holds a promise for using this property to detect the presence of global magnetic fields on Sun-like stars. A large number of K-line profiles were obtained over a variety of plages on the Sun and related the 1A emission flux centered at the K3 minimum for these profiles with the corresponding values of the longitudinal component of the magnetic field. This provides a calibration for detecting and estimating the surface magnetic fields on stars.