期刊
ASTRONOMY & ASTROPHYSICS
卷 592, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201628779
关键词
stars: interiors; stars: evolution; binaries: eclipsing
资金
- Spanish MEC [AYA2015-71718-R]
- NSF [AST-1509375]
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1509375] Funding Source: National Science Foundation
Context. Convective core overshooting extends the main-sequence lifetime of a star. Evolutionary tracks computed with overshootingare very different from those that use the classical Schwarzschild criterion, which leads to rather different predictions for the stellar properties. Attempts over the last two decades to calibrate the degree of overshooting with stellar mass using detached double-lined eclipsing binaries have been largely inconclusive, mainly because of a lack of suitable observational data. Aims. We revisit the question of a possible mass dependence of overshooting with a more complete sample of binaries, and examine any additional relation there might be with evolutionary state or metal abundance Z. Methods. We used a carefully selected sample of 33 double-lined eclipsing binaries strategically positioned in the H-R diagram with accurate absolute dimensions and component masses ranging from 1.2 to 4.4 M-circle dot. We compared their measured properties with stellar evolution calculations to infer semi-empirical values of the overshooting parameter alpha(ov) for each star. Our models use the common prescription for the overshoot distance d(ov) = alpha H-ov(p), where Hp is the pressure scale height at the edge of the convective core as given by the Schwarzschild criterion, and alpha(ov) is a free parameter. Results. We find a relation between alpha(ov) and mass, which is defined much more clearly than in previous work, and indicates a significant rise up to about 2 M-circle dot followed by little or no change beyond this mass. No appreciable dependence is seen with evolutionary state at a given mass, or with metallicity at a given mass although the stars in our sample span a range of a factor of ten in [Fe/H], from -1. 01 to +0.01.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据