Minoru Umezu*
Astronomical Institute, Graduate School of Science, Tohoku
University, Sendai 980-8578, Japan
Abstract. An inefficient convective solution with non - negligible gradient of the mean molecular weight was discovered by extending the mixing-length theory of convection (Umezu & Nakakita 1988). This solution is unstable, but becomes stable if the radiative heat loss from the convective element is negligible. However, since the size of the convective element necessary to stabilize this solution is larger than the stellar radius by several orders, this inefficient convection solution never becomes stable. If the radiative heat loss is neglected, the zone with this inefficient convection solution resembles the Ledoux semiconvection zone. Hence this study might show another reason against the Ledoux semiconvection zone.
Keywords: stars: interiors