Non-linear behaviour of the pulsating white dwarf G29-38 – III. Relative amplitudes of the cross-frequencies |
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| Authors: | François Vuille † Pierre Brassard |
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| Institution: | Department of Astronomy, University of Cape Town, Rondebosch 7700, South Africa; Département de Physique, Universitéde Montréal, CP 6128, Succ. Centre-Ville, Montréal, Québec, Canada H3C 3J7 |
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| Abstract: | In each season when the DA pulsating white dwarf G29-38 has been observed, its period spectrum appears very different, but it always contains a forest of harmonics and cross-frequencies. The ratio of the amplitude of these non-linear frequencies A c to the product of the amplitudes of the corresponding parent modes A 1 A 2 has been measured. The results are compared with the predictions given by three existing theoretical models. Our analysis shows that the non-linear frequencies present in the period spectrum of G29-38 owe their presence mostly to the inelastic response of the stellar medium to the perturbation travelling through it, rather than to the non-linear response of the emergent luminous flux to the surface temperature variation. This analysis also confirms that most identified modes are ?=1, as previously asserted by Kleinman et al. |
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| Keywords: | stars: individual: G29-38 stars: oscillations stars: variables: other white dwarfs |
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