Poster abstract details
Direct detection of dynamo-generated magnetic fields at the surface of fast rotating active single giants.
Abstract
The red giant branch stage enables a good opportunity for understanding the interplay of magnetic field, stellar evolution and the mixing processes. In some stars, the coupling of the deepening convection zone with rotation results in generation of new dynamo-driven magnetic fields. The new generation spectropolarimeters make available a precise detection of magnetic fields
of few Gauss and less. Using the spectropolarimeter NARVAL at TBL (Pic du
Midi Observatory, France) and the LSD technique we have began an extensive
program for magnetic field study in single G-K-M giants. Here we present
the first results for the fast rotating giant stars.
7 of 8 observed fast rotators were detected in Stokes V at different rotational phases up to now. For first time, magnetic field was detected directly at the surface of a fairly evolved active M giant, EK Boo. The behavior of the spectral
lines activity indicators was analysed together with the magnetic field variations.
As a conclusion, the Stokes V and the activity indicators behaviors could be explained in the terms of dynamo-generated fields at the surface of these giants. Taking into account their evolutionary stage and fast rotation, solar type dynamo is likely to operate in them.
of few Gauss and less. Using the spectropolarimeter NARVAL at TBL (Pic du
Midi Observatory, France) and the LSD technique we have began an extensive
program for magnetic field study in single G-K-M giants. Here we present
the first results for the fast rotating giant stars.
7 of 8 observed fast rotators were detected in Stokes V at different rotational phases up to now. For first time, magnetic field was detected directly at the surface of a fairly evolved active M giant, EK Boo. The behavior of the spectral
lines activity indicators was analysed together with the magnetic field variations.
As a conclusion, the Stokes V and the activity indicators behaviors could be explained in the terms of dynamo-generated fields at the surface of these giants. Taking into account their evolutionary stage and fast rotation, solar type dynamo is likely to operate in them.