The magnetic field plays a central role in the life of the star. However, since the star is not transparent, this field has never been able to be seen in the core of the star. For the first time, researchers at the Institute of Astrophysics and Planetology have measured the magnetic field in the core of several red giants.
Red giants are stars that have exhausted hydrogen reserves in their cores and are approaching the end of their life cycle. Such a future awaits, for example, the sun in a few billion years. Turbulent motion on the surface of such stars, caused by the convection, triggers seismic waves that spread within these stars. By observing the surface, they can restore the internal structure to the core and explain to the authors of the study.
Scientists used data from the Kepler satellite to detect magnetic field signatures in fluctuations in the surface of three red giants, and the magnetic field at the core of these stars was between 10 and 130 kgs, about 100,000 times greater than the average magnetic field at the Sun's surface.
To get these results, astrophysicists have identified three red giant stars with abnormal changes on the surface. For most stars, rotation divides each mode of variation into several components regularly separated by frequency. For the three red giants considered, these frequency intervals are irregular.
The theoretical analysis showed that the asymmetries of the fluctuations could be attributed to the presence of a strong magnetic field that outraged the gravitational waves in the core of the star. On the basis of the asymmetries identified, scientists measured the magnetic field's tension and obtained information about its geometry.