CAOSP abstracts, Volume: 27, No.: 3, year: 1998
- Author(s): WADE, G.A.; DONATI, J.-F.; MATHYS, G.; PISKUNOV, N.
- Journal: Contributions of the Astronomical Observatory Skalnate Pleso,
vol. 27, no. 3, p. 436-440.
- Date: 04/1998
- Title: Linear spectropolarimetry of Ap stars: a new degree of constraint on magnetic structure
- Keyword(s): MAGNETIC FIELDS, POLARIZATION, STARS: CHEMICALLY PECULIAR
- Pages: 436 -- 440
Abstract:
We present preliminary results from a programme aimed at acquiring
linear spectropolarimetry of magnetic A and B stars. Linear polarization
in the spectral lines of these objects is due to the Zeeman effect,
and should provide detailed new information regarding the structure
of their strong magnetic fields. To illustrate the impact of these new
data, we compare observed circular and linear polarization line profiles
of 53 Cam with the profiles predicted by the magnetic model by Landstreet.
Linear polarization in the spectral lines of all stars studied is extremely
weak; in most cases, below the threshold of detectability even for very high
SNRs. In order to overcome this problem, we employ the Least-Squares
Deconvolution (LSD) multi-line analysis technique in order to extract
low-noise mean line profiles and polarization signatures from our echelle
spectra. Tests show that these mean signatures can be modelled as real
spectral lines, and have the potential to lead to high-resolution maps
of the magnetic and chemical abundance surface distributions.
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