O. Richard et al., NEW SOLAR MODELS INCLUDING HELIOSEISMOLOGICAL CONSTRAINTS AND LIGHT-ELEMENT DEPLETION, Astronomy and astrophysics, 312(3), 1996, pp. 1000-1011
We have computed new solar models using the same stellar evolution cod
e as described in Charbonnel, Vauclair and Zahn (1992). This code, ori
ginating from Geneva, now includes the computation of element. segrega
tion for helium and 12 heavier isotopes. It may also include any type
of mixing of the stellar gas, provided this mixing can be parametrized
with an effective diffusion coefficient as a function of radius. Here
we introduced rotation-induced mixing as prescribed by Zahn (1992). W
e present five solar models: 1) the standard model, computed with heav
y element abundances as given by Grevesse (1991); 2) a model including
pure element segregation (no mixing outside the convective zone) with
Grevesse (1991) as initial abundances; 3) same model as (2), but iter
ated so that the final abundances are those of Grevesse (1991); 4) a m
odel with both element segregation and rotation-induced mixing, leadin
g to lithium and beryllium depletion consistent with the observations,
with Grevesse (1991) as initial abundances; 5) same model as (4) but
iterated to obtain Grevesse (1991) as final abundances. This model (5)
now represents our best new solar model consistent with the observati
ons. The u = P/rho function computed as a function of radius in these
new solar models are compared to the helioseismological results obtain
ed for the same function by Dziembowski et al (1994). Improving the ph
ysics of the models leads to a better consistency with helioseismology
. In our best model (5), which includes both Segregation and mixing, t
he relative difference in the u function between the model and the hel
ioseismological results is smaller than 0.5 per cent at all radii exce
pt at the center and the surface. Meanwhile lithium is depleted by a f
actor 155 and beryllium by a factor 2.9, which is consistent with the
observations. The bottom of the convective zone lies at a fractional r
adius of 0.716, consistent with helioseismology. The neutrino fluxes a
re not decreased in any of these models. The models including the comp
utations of element segregation lead to a present surface helium abund
ance of: Y-sur f between 0.248 and 0.258, which is in satisfactory agr
eement with the value derived from helioseismology.