ON THE PROFILE OF THE SOLAR P-MODE LINES

It has been shown (Gabriel 1992, 1993) that it is very likely that the lines of the solar p-mode spectrum show some skewness which is relate d to the location and the properties of the excitation source. Asymmet ries have been observed at high frequencies by Duvall et al. (1993) an d possibly by Toutain (1994) at lower frequencies. We had naively thou ght that this skewness could be measured without any prejudice knowled ge of some information on the line shape. This turns out to be difficu lt. On the other hand from the theoretical side we have to face two di fficulties. First we lack good information concerning the source and s econdly, because the linear interactions between convection and pulsat ion are poorly known, we do not have a reliable theory to take all the dissipative effects into account in the integration of the equations of pulsation. In this note, we give a general formula for line profile s using only very general properties of solar oscillations. We first p resent a general discussion of the origin of the line asymmetries. The n we obtain a very general expression for line profiles.