Non-linear behaviour of the pulsating white dwarf G29-38 – II. Analysis of the phase spectrum |
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Authors: | Franç ois Vuille &dagger |
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Affiliation: | Department of Astronomy, University of Cape Town, Rondebosch 7700, South Africa |
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Abstract: | An analysis of the phase spectrum of the DA pulsating white dwarf G29-38 over many seasons has been performed. This complements a companion paper which analyses the evolution of the temporal spectrum of G29-38. We show that, with one exception, the relative phases of the harmonics and combination frequencies are all oscillating in phase with their parent modes. This not only suggests that these non-linear frequencies owe their presence to harmonic distortion and not to resonant mode coupling, but also explains the typical pulse shapes observed in the light curves of large-amplitude variable white dwarfs. The one exceptional cross-frequency that does not show a phasing with its parent modes is thought to be a resonance. |
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Keywords: | stars: individual: G29-38 stars: oscillations stars: variables: other white dwarfs |
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