Abstracts > sorted by Authors > Fournier Damien

The interpretation of solar and stellar observations requires a good understanding of the observables such as velocity or disk-integrated intensity. However, the modeling is often drastically simplified. Here, we model the perturbations in intensity caused by stellar oscillations in an atmosphere using first-order perturbation theory. We take into account the main sources of opacity (absorption and scattering) and solve 1D radiative transfer. From the intensity computed at several positions in the spectral line we also derive (line-of-sight or radial) velocity.
In the solar case, we show that the perturbed intensity differs significantly from commonly-used simplified models. Finally, we model the power spectrum for velocity and disk-integrated intensity and compare the latter to a Sun-as-a-star power spectrum obtained from the VIRGO instrument. We present our results on the Sun but the methodology is general and will be applied to many solar-like stars in the future.