Bibcode
Belkacem, K.; Samadi, R.; Goupil, M. J.; Baudin, F.; Salabert, D.; Appourchaux, T.
Bibliographical reference
Astronomy and Astrophysics, Volume 522, id.L2
Advertised on:
11
2010
Journal
Citations
11
Refereed citations
9
Description
Theoretical modeling of the driving processes of solar-like oscillations
is a powerful way of understanding the properties of the convective
zones of solar-type stars. In this framework, the description of the
temporal correlation between turbulent eddies is an essential ingredient
to model mode amplitudes. However, there is a debate between a Gaussian
or Lorentzian description of the eddy-time correlation function (Samadi
et al. 2003b, A&A, 403, 303; Chaplin et al. 2005, MNRAS, 360, 859).
Indeed, a Gaussian description reproduces the low-frequency shape of the
mode amplitude for the Sun, but is unsatisfactory from a theoretical
point of view (Houdek 2010, Ap&SS, 328, 237) and leads to other
disagreements with observations (Samadi et al. 2007, A&A, 463, 297).
These are solved by using a Lorentzian description, but there the
low-frequency shape of the solar observations is not correctly
reproduced. We reconcile the two descriptions by adopting the sweeping
approximation, which consists in assuming that the eddy-time-correlation
function is dominated by the advection of eddies, in the inertial range,
by energy-bearing eddies. Using a Lorentzian function together with a
cut-off frequency derived from the sweeping assumption allows us to
reproduce the low-frequency shape of the observations. This result also
constitutes a validation of the sweeping assumption for highly turbulent
flows as in the solar case.
Related projects
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary
Savita
Mathur