Poster abstract details

Cartography of the magnetic fields and chemical spots of Ap stars
J. Silvester, O. Kochukhov, G. Wade, N. Piskunov, J. Landstreet, S. Bagnulo, D. Hanes

Abstract

We will introduce a project using the ingenious technique of Magnetic Doppler Imaging (MDI) to create assumption-free vector magnetic field maps and chemical surface structure maps of chemically peculiar A and B type (or Ap) stars. We are exploiting the latest generation of spectropolarimeters (Narval at the Pic du Midi observatory, and ESPaDOnS at the Canada-France-Hawaii telescope), to obtain high-resolution time series of Stokes IQUV spectra of a selection of Ap stars. The spectra have superior signal-to-noise ratio, resolution and wavelength coverage to those used previously, this combined with the ground-breaking inversion techniques introduced by Kochukhov et al. in 2002 results in maps which represent the state-of-the-art in the field of stellar cartography. These maps will allow us to better understand the links between the magnetic field and the physical processes leading to the formation of chemical structures in the photosphere and allow us to address questions surrounding the detailed magnetic field geometry of Ap stars, leading to a better understanding of the origins of the magnetic fields of intermediate- and high-mass stars.