Bi-dimensional element stratifications computed for magnetic Ap star atmospheres
- G. Alecian, M. Stift, M. Stift
- Physics, Geology
- 1 June 2010
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 most…
The magnetic field and circumstellar environment of the helium-strong star HD 36485 =δ Ori C
- F. Leone, D. Bohlender, M. Stift
- Physics
- 1 February 2010
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 strongly…
Measuring stellar magnetic fields from high resolution spectroscopy of near-infrared lines
Zeeman splitting of otherwise degenerate levels provides a straight-forward method of measuring stellar magnetic fields. In the optical, the relative displacements of the Zeeman components are quite…
Modelling the incomplete Paschen–Back effect in the spectra of magnetic Ap stars
- M. Stift, F. Leone, E. L. Degl'innocenti
- Physics
- 17 January 2008
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 level…
Time-dependent diffusion in stellar atmospheres
- G. Alecian, M. Stift, E. Dorfi
- Physics
- 1 December 2011
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 only…
A study of polarized spectra of magnetic CP stars: Predicted vs. observed Stokes IQUV profiles for $\beta$ CrB and 53 Cam
- S. Bagnulo, G. Wade, M. Stift
- Physics
- 1 April 2001
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 were…
Three-dimensional abundance distributions in ApBp star atmospheres: non-axisymmetric magnetic geometry
- G. Alecian, M. Stift
- Physics
- 27 February 2017
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 the…
Multiline Zeeman Signatures Through Line Addition
- M. Semel, J. Vélez, INAF-Catania
- Physics
- 23 June 2009
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 the…
Modelling ApBp star atmospheres with stratified abundances consistent with atomic diffusion
- M. Stift, G. Alecian
- Environmental Science, Physics
- 1 October 2012
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 ever…
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