  Helioseismology has provided very precise information about the solar
internal sound speed and density throughout most of the solar interior. The
results are generally quite close to the properties of standard solar models.
Since the solar oscillation frequencies do not provide direct information about
temperature and composition, the helioseismic results to not completely rule
out an astrophysical solution to the discrepancy between the predicted and
measured neutrino fluxes from the Sun. However, such a solution does appear
rather implausible.
