  Despite the strong evidence that the peaks in the spectrum of solar
oscillations are asymmetric, most determinations of mode frequencies have been
based on fits of symmetric Lorentzian profiles to the Fourier or power spectra
of oscillation time strings. The systematic errors resulting from neglecting
the line asymmetry could have serious effects on inversions for the solar
internal structure and rotation. Here we analyse artificial data based on
simple models of the intrinsic line asymmetry, using GONG mode parameters with
asymmetries found by one of us (Rosenthal \cite{rosenthal2}). By fitting
Lorentzians to the resulting spectra, we estimate the likely properties of the
errors introduced in the frequencies. We discuss whether these frequency shifts
have a form similar to the near-surface layers uncertainties and are therefore
suppressed in the solar structure inversion. We also estimate directly their
contribution, if any, in the solar sound-speed and density determinations using
the SOLA technique.
