CFHT UM2025 - Presentation Details
Abstract Details
Title: Extending Zeeman-Doppler Imaging to Pulsating Magnetic Stars
Presenter: Chloe Gutteridge
Abstract:
Zeeman-Doppler Imaging (ZDI) is a technique that inverts a series of spectropolarimetric data allowing the reconstruction of stellar magnetic fields, which provides valuable insights into their strength, geometries, and time evolution. However, ZDI assumes that stellar line profile variations are due solely to rotation - an assumption that breaks down for pulsating stars, where oscillations introduce additional Doppler shifts. By modelling the pulsation modes identified with spectroscopic/spectropolarimetric and photometric observations, we can create a time-dependent surface velocity map which accounts for all causes of Doppler shifts of local lines. This allows the causes of line profile variations associated with rotation, i.e. magnetic fields and spots, to be accurately assigned locations on the stellar surface preventing errors in the magnetic field strength and geometry; and spot locations, relative brightness, and sizes. This is crucial for obtaining the correct stellar and magnetic properties. We present a modification of the open-source ZDIpy code by Folsom et al. (2018), adapted for pulsating stars. By applying this updated method for the first time to both modelled and real pulsators, and then comparing it to the original code, we demonstrate its necessity for extending magnetic mapping to pulsating stars and future precise magneto-asteroseismic analysis.