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Oscillation power spectra of the Sun and of Alpha Cen A: observations versus models

R. Samadi·M. J. Goupil·F. Baudin·D. Georgobiani·R. Trampedach·R. Stein·A. Nordlund
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Abstract

Hydrodynamical, 3D simulations of the outer layers of the Sun and Alpha Cen A are used to obtain constraints on the properties of turbulent convection in such stars. These constraints enable us to compute - on the base of a theoretical model of stochastic excitation - the rate P at which p modes are excited by turbulent convection in those two stars. Results are then compared with solar seismic observations and recent observations of Alpha Cen A. For the Sun, a good agreement between observations and computed P is obtained. For Alpha Cen A a large discrepancy is obtained which origin cannot be yet identified: it can either be caused by the present data quality which is not sufficient for our purpose or by the way the intrinsic amplitudes and the life-times of the modes are determined or finally attributed to our present modelling. Nevertheless, data with higher quality or/and more adapted data reductions will likely provide constraints on the p-mode excitation mechanism in Alpha Cen A.

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R. Samadi, M. J. Goupil, F. Baudin, D. Georgobiani, R. Trampedach, R. Stein, A. Nordlund. 2004-09-14. Oscillation power spectra of the Sun and of Alpha Cen A: observations versus models. https://arxiv.org/abs/astro-ph/0409325

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