EDP Sciences
Free Access
Volume 370, Number 1, April IV 2001
Page(s) 136 - 146
Section Formation, structure and evolution of stars
DOI https://doi.org/10.1051/0004-6361:20010212

A&A 370, 136-146 (2001)
DOI: 10.1051/0004-6361:20010212

Excitation of stellar p-modes by turbulent convection

I. Theoretical formulation
R. Samadi1, 2 and M.-J. Goupil3

1  Observatoire de Paris, DESPA, CNRS UMR 8632, 92195 Meudon, France
2  Astronomy Unit, Queen Mary, University of London, London E14NS, UK
3  Observatoire de Paris, DASGAL, CNRS UMR 8633, 92195 Meudon, France

(Received 17 October 2000 / Accepted 19 January 2001)

Stochatic excitation of stellar oscillations by turbulent convection is investigated and an expression for the power injected into the oscillations by the turbulent convection of the outer layers is derived which takes into account excitation through turbulent Reynolds stresses and turbulent entropy fluctuations. This formulation generalizes results from previous works and is built so as to enable investigations of various possible spatial and temporal spectra of stellar turbulent convection. For the Reynolds stress contribution and assuming the Kolmogorov spectrum we obtain a similar formulation to those derived by previous authors. The entropy contribution to excitation is found to originate from the advection of the Eulerian entropy fluctuations by the turbulent velocity field. Numerical computations in the solar case in a companion paper indicate that the entropy source term is dominant over the Reynold stress contribution to mode excitation, except at high frequencies.

Key words: convection -- turbulence -- stars: oscillations -- Sun: oscillations

Offprint request: R. Samadi, Reza.Samadi@obspm.fr

© ESO 2001