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Adiabatic exponent in isentropic convective zone: a heavy elements abundance and seismic inversion

Auteur

Baturin Vladimir

Institution

Sternberg Astronomical Institute

Theme

Solar and stellar modelling

Abstract

Profile of adiabatic exponent along isentropic curve is considered in a view of the low-Z photospheric abundances problem and possibility of determination of the CO and Ne contents in the solar convective zone. Tiny variations of the adiabatic exponent are caused by sequential ionizations of elements. If an ionization stage is isolated from others, it leads to a swallow depression of the adiabatic exponent, what could be traced on a seismically inverted profile. Position of the depression region depends on entropy of the isentropic curve and the partition function of ions, which are essential parts of an equation of state. With an extended version of SAHA-S EOS we are able to study traces of elements in the exponent profile and give estimation of the element contents.
We present the effect of content variations of main heavy elements and give estimations on their abundance according to the recently inverted profile of the adiabatic exponent. Results do not reveal indications on low-Z abundances in the deep adiabatic part of the convection zone in contrast to its photospheric determination.
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