The age of the Sun and the relativistic corrections in the EOS

We show that the inclusion of special relativistic corrections in the revised OPAL and MHD equations of state has a significant impact on the helioseismic determination of the solar age. Models with relativistic corrections included lead to a reduction of about 0.05-0.08 ; Gyr with respect to those obtained with the old OPAL or MHD EOS. Our best-fit value is t_seis = (4.57 +/- 0.11) ; Gyr which is in remarkably good agreement with the meteoritic value for the solar age. We argue that the inclusion of relativistic corrections is important for probing the evolutionary state of a star by means of the small frequency separations delta nu _l,n=nu _l,n-nu _l+2,n-1, for spherical harmonic degrees l = 0,1 and radial order n >> l.