CFHT UM2025 - Presentation Details
Abstract Details
Title: Results from the first spectropolarimetric survey of magnetism in gamma Dor pulsators
Presenter: Jonathan Labadie-Bartz
Abstract:
Strong magnetic fields are found in about 10% of stars in the upper main sequence, but to date there have been no reported magnetic detections in the gamma Doradus (gDor) pulsators. The gDor stars are intermediate mass (~1.3 - 2 Msun, or late A- to early F- type), and exhibit g mode pulsation. These pulsation modes propagate deep into the stellar interior, and thus encode information about the near-core layers, making gDor pulsators the optimal class of intermediate-mass stars to determine their innermost properties via asteroseismology. Magnetism can fundamentally alter interior processes, such as chemical mixing and angular momentum transport. However, stellar structure and evolutionary models require observational calibrations in order to describe stellar interiors and the role of magnetism. To address this, we have conducted a spectropolarimetric survey of about 50 gDor stars with ESPaDOnS at CFHT to determine the surface magnetic field properties of the gDor population for the first time. Our investigation of the magnetic properties of this sample will be described, including detections and non-detections, plus the space photometry from the TESS and Kepler missions which drove our target selection process and encodes the pulsational signals that enable asteroseismic analysis. The observed small magnetic detection occurrence in gDor stars highlights the need for theoretical and modeling work to understand interactions between magnetic fields and the sub-surface convection zones that drive gDor pulsation.