P-modes in rapidly rotating stars -- looking for regular patterns in synthetic asymptotic spectra

Abstract

According to a recent ray-based asymptotic theory, the high-frequency p-mode spectrum of rapidly rotating stars is a superposition of frequency subsets associated with dynamically independent regions of the ray-dynamics phase space. At high rotation rates corresponding to typical $\delta$ Scuti stars, two frequency subsets are expected to be visible : a regular frequency subset described by a Tassoul like formula and an irregular frequency subset with specific statistical properties. In this paper, we investigate whether the regular patterns can be detected in the resulting spectrum. We compute the autocorrelation function of synthetic spectra where the frequencies follow the asymptotic theory, the relative amplitudes are simply given by the modes' disk-averaging factors, and the frequency resolution is that of a CoRoT long run. Our first results are that (i) the detection of regular patterns strongly depends on the ratio of regular over irregular modes, (ii) low inclination angle configurations are more favorable than near equator-on configurations, (iii) in the absence of differential rotation, the $2\Omega$ rotational splitting between $m=1$ and $m=-1$ modes is an easy feature to detect.

4 pages, 4 figures, proceedings of the HELAS-IV International Conference, accepted for publication in Astronomische Nachrichten

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• Mode visibilities in rapidly rotating stars
• Unexpected series of regular frequency spacing of delta Scuti stars in the non-asymptotic regime -- II. Sample -- echelle diagrams and rotation
• Regular Oscillation Sub-spectrum of Rapidly Rotating Stars
• Frequency regularities of acoustic modes and multi-colour mode identification in rapidly rotating stars
• Effects of a strong magnetic field on internal gravity waves: trapping, phase mixing, reflection and dynamical chaos
• Unexpected series of regular frequency spacing of delta Scuti stars in the non-asymptotic regime -- I. The methodology
• Magneto-gravity wave packet dynamics in strongly magnetised cores of evolved stars
• The Delta Scuti star 38 Eri from the ground and from space
• Internal rapid rotation and its implications for stellar structure and pulsations
• Global Helioseismology