A more realistic representation of overshoot at the base of the solar convective envelope as seen by helioseismology

Abstract

The stratification near the base of the Sun's convective envelope is governed\nby processes of convective overshooting and element diffusion, and the region\nis widely believed to play a key role in the solar dynamo. The stratification\nin that region gives rise to a characteristic signal in the frequencies of\nsolar p modes, which has been used to determine the depth of the solar\nconvection zone and to investigate the extent of convective overshoot. Previous\nhelioseismic investigations have shown that the Sun's spherically symmetric\nstratification in this region is smoother than that in a standard solar model\nwithout overshooting, and have ruled out simple models incorporating\novershooting, which extend the region of adiabatic stratification and have a\nmore-or-less abrupt transition to subadiabatic stratification at the edge of\nthe overshoot region. In this paper we consider physically motivated models\nwhich have a smooth transition in stratification bridging the region from the\nlower convection zone to the radiative interior beneath. We find that such a\nmodel is in better agreement with the helioseismic data than a standard solar\nmodel.\n