Thursday 3 February 2011, by Mario Monteiro (Director Centro de Astrofisica, Universidade do Porto, Portugal)
Tuesday 15 February 2011 à 11h00 , Lieu : Salle de confĂ©rence du bât. 17
The stratification near the base of the Sun’s convective envelope is
governed by processes of convective overshooting and element diffusion,
and the region is widely believed to play a key role in the solar
dynamo. The stratification in that region gives rise to a characteristic
signal in the frequencies of solar p modes, which has been used to
determine the depth of the solar convection zone and to investigate the
extent of convective overshoot.
Previous helioseismic investigations have shown that the Sun’s
spherically symmetric stratification in this region is smoother than
that in a standard solar model without overshooting, and have ruled out
simple models incorporating overshooting, which extend the region of
adiabatic stratification and have a more-or-less abrupt transition to
subadiabatic stratification at the edge of the overshoot region.
In this talk we discuss the constraints from Helioseismology, reported
in http://xxx.lanl.gov/abs/1102.0235, through a detailed comparison with
the Sun of physically motivated models which have a smooth transition in
stratification bridging the region from the lower convection zone to the
radiative interior beneath. We find that such a model is in better
agreement with the helioseismic data than a standard solar model.
The seismic method developed to produce this analysis is discussed as
well as the implications that such a result may have for the
interpretation of seismic data of other solar-type stars.
