Evidence of the connection between internal magnetic fields and chromospheric activity in late-type stars.

In this work an attempt is made to establish a connection between the dynamo effect, which operates in the convection zone of late-type stars, and the chromospheric activity observed in these objects. An estimate is made, in a theoretical way, for a sample of main-sequence active stars with spectral types G and K, the magnetic field generated in a region close to the base of the convection zone and the filling factor (fraction of stellar surface covered by strong magnetic fields). The analysis of the behavior both of the filling factor and the activity indicator R(Ca II+Mg II) against several stellar parameters (B-V and the Rossby number) supports the existence of a link between the interior processes and the surface activity.