Properties of semi-convection and convective overshooting for massive stars

• Published in: arXiv.org 2013-11
• Main Authors: Cai Yun Ding, Li, Yan
• Format: Article
• Language: English
• Subjects: Convection; Massive stars; Mathematical analysis; Parameters
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1311.7465

Properties of semi-convection and core convective overshooting of stars with 15 \(M_{\odot}\) and 30 \(M_{\odot}\) are calculated in the present paper. New methods are used to deal with semi-convection. Different entropy gradient is used when adopting the Schwarzschild method and the Ledoux method which are used to confine the convective boundary and to calculate the turbulent quantities: \(\frac{\partial \overline{s}}{\partial r}=-\frac{c_{p}}{H_P}(\nabla-\nabla_{\rm ad})\) when the Schwarzschild method is adopted and \(\frac{\partial \overline{s}}{\partial r}=-\frac{c_{p}}{H_P}(\nabla-\nabla_{\rm ad}-\nabla_{\mu})\) when the Ledoux method is adopted. Core convective overshooting and semi-convection are treated as a whole part and the development of them are found to present nearly opposite tendency, more intensive core convective overshooting lead to weaker semi-convection. The influences of different parameters and the convection processing methods on the turbulent quantities are analyzed in this paper. Increasing the mixing-length parameter \(\alpha\) leads to more turbulent dynamic energy in the convective core and prolonging the overshooting distance but depressing the development of semi-convection. The Ledoux method adopted leads to overshooting extending further and semi-convection developing suppressed.