Can we use binary stars to study the stellar dynamo?

by Felipe H. Navarrete (Hamburg Observatory)

Tuesday 2 Jun 2020, 15:00 → 16:00 Europe/Stockholm

https://stockholmuniversity.zoom.us/j/940229961

https://ui.adsabs.harvard.edu/abs/2020MNRAS.491.1043N/abstract

Binary stars are routinely used to derive stellar parameters and test the stellar evolution theory. Post-common-envelope binaries are a particular kind of binaries, commonly composed of a white dwarf and a low-mass main-sequence star. Observations over tens of year of the eclipsing times show quasi-periodic deviations from the expected eclipsing times. One explanation links the dynamo action in the main-sequence star to its gravitational quadrupole moment (Q), therefore changing the binary separation and thus reproducing the observations. We are currently working on linking the variations in Q to magnetic activity from 3D MHD simulations and making observable predictions. I will summarize our recent findings, which indicate that the magnetic field evolution is followed by the evolution of Q, making post-common-envelope binaries good candidates to study stellar dynamos.