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Session 101 - The Sun.
Display session, Thursday, January 18
North Banquet Hall, Convention Center
We analyze p-mode line profiles using both a simplified one-dimensional model and a realistic solar model. We find asymmetry to be a general feature of the profiles, which depends on source location, mode frequency, mode spherical harmonic degree, and linewidth, but not on the particular mechanism or location of damping. Using the realistic solar model, we calculate the dependence of line asymmetry on source location, mode frequency, and spherical harmonic degree, and provide physical explanations of our results in terms of the simplified model. Our results are in qualitative agreement with the observational results of Duvall et al. (1993) if we assume the sources are located within the top 400 km of the solar convection zone, but more detailed observations of line asymmetry in velocity spectra are called for to accurately locate the sources. We find that line asymmetry in both the simplified model and the realistic solar model causes the frequencies obtained from Lorentzian fits to the power spectrum to differ from the corresponding eigenfrequencies by an amount which is proportional to the asymmetry of the peak as quantified in a model-independent way, and to the linewidth.
Program listing for Thursday