SIMBAD references

2009A&A...508..345B - Astronomy and Astrophysics, volume 508, 345-353 (2009/12-2)

Mode excitation by turbulent convection in rotating stars. I. Effect of uniform rotation.

BELKACEM K., MATHIS S., GOUPIL M.J. and SAMADI R.

Abstract (from CDS):

We focus on the influence of the Coriolis acceleration on the stochastic excitation of oscillation modes in convective regions of rotating stars. Our aim is to estimate the asymmetry between excitation rates of prograde and retrograde modes. We extend the formalism derived for obtaining stellar p- and g-mode amplitudes (Samadi & Goupil, 2001A&A...370..136S, Belkacem et al., 2008A&A...478..163B) to include the effect of the Coriolis acceleration. We then study the special case of uniform rotation for slowly rotating stars by performing a perturbative analysis. This allows us to consider the cases of the Sun and the CoRoT target HD49933. We find that, in the subsonic regime, the influence of rotation as a direct contribution to mode driving is negligible compared to the Reynolds stress contribution. In slow rotators, the indirect effect of the modification of the eigenfunctions on mode excitation is investigated by performing a perturbative analysis of the excitation rates. The excitation of solar p modes is found to be affected by rotation with excitation-rate asymmetries between prograde and retrograde modes of the order of several percent. Solar low-order g modes are also affected by uniform rotation and their excitation-rate asymmetries are found to reach 10%. The CoRoT target HD49933 is rotating more rapidly than the Sun (Ω/Ω≃8), and we show that the resulting excitation-rate asymmetry is about 10% for the excitation rates of p modes. We demonstrate that p and g mode excitation rates are modified by uniform rotation through the Coriolis acceleration. A study of the effect of differential rotation will be presented in a forthcoming paper.

Abstract Copyright:

Journal keyword(s): convection - turbulence - stars: oscillations

Simbad objects: 1

goto Full paper

goto View the references in ADS

To bookmark this query, right click on this link: simbad:2009A&A...508..345B and select 'bookmark this link' or equivalent in the popup menu