Astronomy and Astrophysics – Astrophysics
Scientific paper
Apr 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001a%26a...369..889b&link_type=abstract
Astronomy and Astrophysics, v.369, p.889-907 (2001)
Astronomy and Astrophysics
Astrophysics
38
Stars: Magnetic Fields, Polarization, Stars: Chemically Peculiar, Stars: Individual: Beta Crb, Stars: Individual: 53 Cam
Scientific paper
We present a comparison of observed and calculated Stokes IQUV spectra of two well-known magnetic chemically peculiar stars, beta Coronae Borealis and 53 Camelopardalis. The observed Stokes spectra were recently described by Wade et al. (\cite{wad00a}), and have been complemented with additional circularly polarized spectra obtained at the Special Astrophysical Observatory. The calculated spectra represent the predictions of new and previously published magnetic field models derived from the analysis of some surface averaged field estimates (e.g., longitudinal field, magnetic field modulus, etc.). We find that these magnetic models are not sufficient to account fully for the observed Stokes profiles - particularly remarkable is the disagreement between the predicted and observed Stokes Q and U profiles of 53 Cam. We suggest that this should be interpreted in terms of magnetic morphologies which are significantly more complex than the second-order multipolar expansions assumed in the models. However, it is clear that some of our inability to reproduce the detailed shapes of the Stokes IQUV profiles is unrelated to the magnetic models. For many metallic ions, for both stars, we found it impossible to account for the strengths and shapes of the observed spectral line profiles when we adopted a unique value for the individual ion abundance. We suggest that this results from strongly non-uniform distributions of these ions as a function of optical depth (i.e., chemical stratification), a hypothesis that is supported by comparison with simple chemically stratified models. Based on observations obtained with the 2 m Bernard Lyot telescope of the Pic-du-Midi Observatory, the 1 m telescope of the Special Astrophysical Observatory, and the 0.9 m telescope of the Osservatorio Astrofisico di Catania.
Bagnulo Stefano
Donati Jean-Francois
Landstreet John Darlington
Leone Francesco
Monin D. N.
No associations
LandOfFree
A study of polarized spectra of magnetic CP stars: Predicted š. observed Stokes IQUV profiles for beta CrB and 53 Cam does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A study of polarized spectra of magnetic CP stars: Predicted š. observed Stokes IQUV profiles for beta CrB and 53 Cam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A study of polarized spectra of magnetic CP stars: Predicted š. observed Stokes IQUV profiles for beta CrB and 53 Cam will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1181818