论文标题
金属性对旋转和磁性恒星旋转演变的影响
The Impact of Metallicity on the Evolution of Rotation and Magnetic Activity of Sun-Like Stars
论文作者
论文摘要
已知恒星和低质量（<1.4 msun）主序列的旋转速率和磁性活动随时间而下降，现在存在几种模型，用于旋转和活动的演变。但是，尚未探索化学成分在恒星旋转过程中的作用。在这项工作中，我们使用结构性进化代码来计算具有三种不同质量（0.7、1.0和1.3msun和六种不同金属的恒星的旋转演化，从[Fe/H] = -1.0到[Fe/H] =+0.5。我们还实施了三种不同的风能（两种现代和一个经典的效果），并在进行了三种不同的风能，以对其进行了竞争，并进行了旋转的预测，并进行了旋转的预测。结构性特性，尤其是对流的离职时间尺度，导致两个现代风力制剂预测扭矩对金属性的强烈依赖。 [Fe/h] = -0.3的旋转周期少于20天，即使旧金属差的恒星在给定的年龄较大，因此它们的旋转速度更快，因此预计磁性活动水平较低。
The rotation rates and magnetic activity of Sun-like and low-mass (< 1.4 Msun) main-sequence stars are known to decline with time, and there now exist several models for the evolution of rotation and activity. However, the role that chemical composition plays during stellar spin-down has not yet been explored. In this work, we use a structural evolution code to compute the rotational evolution of stars with three different masses (0.7, 1.0, and 1.3Msun and six different metallicities, ranging from [Fe/H]=-1.0 to [Fe/H]=+0.5. We also implement three different wind-braking formulations from the literature (two modern and one classical) and compare their predictions for rotational evolution. The effect that metallicity has on stellar structural properties, and in particular the convective turnover timescale, leads the two modern wind-braking formulations to predict a strong dependence of the torque on metallicity. Consequently, they predict that metal rich stars spin-down more effectively at late ages (> 1 Gyr) than metal poor stars, and the effect is large enough to be detectable with current observing facilities. For example, the formulations predict that a Sun-like (solar-mass and solar-aged) star with [Fe/H]=-0.3 will have a rotation period of less than 20 days. Even though old, metal poor stars are predicted to rotate more rapidly at a given age, they have larger Rossby numbers and are thus expected to have lower magnetic activity levels. Finally, the different wind-braking formulations predict quantitative differences in the metallicity-dependence of stellar rotation, which may be used to test them.
