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Bi-dimensional element stratifications computed for magnetic Ap star atmospheres
Context. Theoretical modelling of abundance stratifications and surface distributions of chemical elements in Ap stars constitutes a major challenge. The atomic diffusion model provides the mostExpand
The magnetic field and circumstellar environment of the helium-strong star HD 36485 =δ Ori C
Extensive Hα spectroscopy of the cool, helium-strong star δ Ori C obtained over two decades has enabled a detailed analysis of the variable Hα emission observed in this sharp-lined and stronglyExpand
Modelling the incomplete Paschen–Back effect in the spectra of magnetic Ap stars
We present preliminary results of a systematic investigation of the incomplete Paschen–Back effect in magnetic Ap stars. A short overview of the theory is followed by a demonstration of how levelExpand
Time-dependent diffusion in stellar atmospheres
The chemical peculiarities of Ap stars are due to abundance stratifications produced by atomic diffusion in their outer layers. Theoretical models can predict such stratifications, but so far onlyExpand
Multiline Zeeman Signatures Through Line Addition
In order to get a significant Zeeman signature in the polarised spectra of a magnetic star, we usually 'add' the contributions of numerous spectral lines; the ultimate goal is to recover theExpand
A study of polarized spectra of magnetic CP stars: Predicted vs. observed Stokes IQUV profiles for $\beta$ CrB and 53 Cam
We present a comparison of observed and calculated Stokes IQUV spectra of two well-known magnetic chemically peculiar stars, Coronae Borealis and 53 Camelopardalis. The observed Stokes spectra wereExpand
Modelling ApBp star atmospheres with stratified abundances consistent with atomic diffusion
Elemental abundances have been found – both empirically and theoretically – to be stratified in the magnetic atmospheres of many chemically peculiar (CP) stars, but these findings are rarely if everExpand
Spectropolarimetric multi line analysis of stellar magnetic fields
Aims. In this paper we study the feasibility of inferring the magnetic field from polarized multi line spectra using two methods: The pseudo line approach and The PCA-ZDI approach. Methods. We useExpand
Three-dimensional abundance distributions in ApBp star atmospheres: non-axisymmetric magnetic geometry
Numerical models for the atmospheres of magnetic ApBp stars have in the past dealt only with centred dipole magnetic field geometries. These models include atomic diffusion that stratifies theExpand