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Title: Calibrating the updated overshoot mixing model on eclipsing binary stars: HY Vir, YZ Cas, χ{sup 2} Hya, and VV Crv

Detached eclipsing binary stars with convective cores provide a good tool to investigate convective core overshoot. It has been performed on some binary stars to restrict the classical overshoot model which simply extends the boundary of the fully mixed region. However, the classical overshoot model is physically unreasonable and inconsistent with helioseismic investigations. An updated model of overshoot mixing was established recently. There is a key parameter in the model. In this paper, we use observations of four eclipsing binary stars, i.e., HY Vir, YZ Cas, χ{sup 2} Hya, and VV Crv, to investigate a suitable value for the parameter. It is found that the value suggested by calibrations on eclipsing binary stars is the same as the value recommended by other methods. In addition, we have studied the effects of the updated overshoot model on the stellar structure. The diffusion coefficient of convective/overshoot mixing is very high in the convection zone, then quickly decreases near the convective boundary, and exponentially decreases in the overshoot region. The low value of the diffusion coefficient in the overshoot region leads to weak mixing and a partially mixed overshoot region. Semi-convection, which appears in the standard stellar models of low-mass stars with convectivemore » cores, is removed by partial overshoot mixing.« less
Authors:
;  [1]
  1. Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)
Publication Date:
OSTI Identifier:
22356771
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; CALIBRATION; DIFFUSION; ECLIPSE; MIXING; STAR EVOLUTION