Contributed Talk - Splinter Magnetic

Thursday, 24 September 2020, 17:35   (virtual room H)

Far Beyond the Sun: The First Stellar Magnetic Butterfly Diagram

Alvarado-Gómez, Hussain, Drake, Sanz-Forcada, Stelzer, Donati, Cohen, Garraffo, Moschou
AIP, ESO, SAO, INTA, Uni. Tübingen, CNRS-IRAP, UMass Lowell, Harvard U., SAO

A former member of the Hyades cluster, iota Horologii (iota Hor) is a ~625 Myr old Sun-like star which displays the shortest coronal activity cycle known to date (P ⋍ 1.6 yr). This object is one of the youngest stars with a detected X-ray activity cycle. The link between activity cycles and the characteristics of the surface magnetic field is a fundamental piece of information to understand the origin of stellar magnetism in late-type stars. In this talk I will present the final results of a long-term observing campaign aimed at studying the evolution of the magnetic cycle of iota Hor, using ground-based high-resolution spectropolarimetry. Employing the technique of Zeeman Doppler Imaging (ZDI), we have successfully detected double polarity reversals in the radial and azimuthal components of the large-scale magnetic field. Furthermore, taking advantage of the short activity cycle and the two-dimensional information resulting from ZDI, we have reconstructed for the first time a magnetic butterfly diagram for a star other than the Sun. We expect that this data set would become a cornerstone for dynamo studies in the Sun and other cool stars.