Issue |
A&A
Volume 455, Number 1, August III 2006
|
|
---|---|---|
Page(s) | 227 - 234 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20064876 | |
Published online | 31 July 2006 |
A new method for the spectroscopic identification of stellar non-radial pulsation modes
I. The method and numerical tests
Institut für Astronomie der Universität Wien, Türkenschanzstr. 17, 1180 Wien, Austria e-mail: zima@ster.kuleuven.be
Received:
18
January
2006
Accepted:
27
March
2006
Aims.We present the Fourier parameter fit method, a new method for spectroscopically identifying stellar radial and non-radial pulsation modes based on the high-resolution time-series spectroscopy of absorption-line profiles. In contrast to previous methods this one permits a quantification of the statistical significance of the computed solutions. The application of genetic algorithms in seeking solutions makes it possible to search through a large parameter space.
Methods.The mode identification is carried out by minimizing , using the observed amplitude and phase across the line profile and their modeled counterparts. Computations of the theoretical line profiles are based on a stellar displacement field, which is described as superposition of spherical harmonics and that includes the first order effects of the Coriolis force.
Results.We made numerical tests of the method on a grid of different mono- and multi-mode models for in order to explore its capabilities and limitations. Our results show that whereas the azimuthal order m can be unambiguously identified for low-order modes, the error of
is in the range of
. The value of m can be determined with higher precision than with other spectroscopic mode identification methods. Improved values for the inclination can be obtained from the analysis of non-axisymmetric pulsation modes. The new method is ideally suited to intermediatley rotating δ Scuti and β Cephei stars.
Key words: line: profiles / techniques: spectroscopic / stars: variables: general
© ESO, 2006
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