Effect of line asymmetry on determination of high-degree mode frequencies

Accurate measurements of frequencies of high-degree p-modes are important for diagnostics of the structure and dynamics of the upper convective boundary layer, and understanding the nature of the solar-cycle variations detected in low- and medium-degree mode frequencies. Neglecting line asymmetry in the peak-bagging approach may lead to systematic errors in the determination of the mode characteristics and, hence, may affect the results of inversions. Here we demonstrate how the p-mode frequencies are systematically changed in the range of ℓ ≤ 1000, ν ≤ 7 mhz when line asymmetry is taken into account in the fitting of the spectral power peaks. The results reported are based upon spectra that were created from observations obtained from the MDI Full-Disk Program during the 1996 SOHO/MDI Dynamics Run.