Semiclassical approximation for low-degree stellar p modes – I. The classical eigenfrequency equation |
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Authors: | I W Roxburgh S V Vorontsov |
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Institution: | Astronomy Unit, Queen Mary and Westfield College, Mile End Road, London E1 4NS;Observatoire de Paris, Place Jules Janssen, 92155 Meudon, France;Institute of Physics of the Earth, B. Gruzinskaya 10, Moscow 123810, Russia |
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Abstract: | A new eigenfrequency equation for low-degree solar-like oscillations in stars is developed, based on the assumption of purely classical propagation in the stellar interior of acoustic waves modified by buoyancy and gravity . Compared with high-frequency asymptotic analysis, the eigenfrequency equation has a new functional form, with expansion in powers of ?(?+1) instead of 1/ ω . Basic observable quantities, the 'large' and 'small' frequency separations , are interpreted as the dependence on frequency and refraction angle of a classical action integral for waves propagating close to the stellar diameter. The new eigenfrequency equation gives a significant improvement in accuracy over previous analyses when tested with solar p modes, suggesting this as an alternative and more powerful tool for applications in stellar seismology. |
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Keywords: | waves methods: numerical stars: oscillations |
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