14th December 2020: Tau 9 Eri : discovery of a new short-period intermediate-mass binary system containing a magnetic star

Speaker: Gregg Wade (Royal Military College, Canada). Location: Virtually; 3 pm


The origin of the fossil magnetic fields present in some intermediate-mass and high-mass stars remains a mystery. A valuable clue may be the dearth of such fields detected in stars resident in close binary systems. Recently we identified the magnetic star Tau 9 Eri to actually be a double-lined spectroscopic binary, making it the most nearby binary system containing an early-type magnetic star. Using circular polarization spectra obtained at the Canada-France-Hawaii telescope, we carried out orbital and magnetic analysis of the system, determining the physical parameters of the two stellar components and the magnetic field geometry of the more massive primary star. We also analyzed space photometry measurements of the system obtained by 3 independent satellites, detecting brightness modulation on a variety of timescales. As a consequence we have identified the primary component as a multi-mode gravity-wave pulsating star, establishing it as a new addition to the small number of objects suitable for sounding of their interior structure using the young science of “magneto-asteroseismology”.

Nach oben scrollen