论文标题
行星吞噬对金属贫困主恒星恒星旋转的影响
The influence of planetary engulfment on stellar rotation in metal-poor main-sequence stars
论文作者
论文摘要
陀螺的方法将其恒星的年龄与旋转时期联系起来。但是，文献中报道了最近偏离陀螺仪关系偏差的证据。在这里，我们研究了恒星与其伴侣之间潮汐相互作用对恒星旋转速度的影响，以解释特殊的恒星旋转速度。恒星及其行星的相互作用使用了一个综合数值框架，该框架结合了潮汐摩擦，磁制动，行星迁移以及GARSTEC网格的详细演化模型。我们专注于从1到20 m $ _ {JUP} $绕的低质量，0.8和1 m $ _ {\ odot} $，具有广泛金属性范围从[Fe/H] = -1到太阳能的主序列的星星。我们的模拟表明，恒星与其伴侣之间的动态相互作用可以具有不同的结果，这取决于最初的半束轴和行星的质量，以及其宿主星的质量和金属性。在大多数情况下，尤其是在行星吞噬的情况下，我们发现恒星旋转速度从1 kms $^{ - 1} $增加到40 kms $^{ - 1} $的灾难性增加，而恒星仍在主要序列上。我们模型的主要预测是，低质量旋转速度的低质量主序列恒星在低金属性上应该更为普遍，因为在所有金属度上，较低的[Fe/H]有利于更快的行星吞噬速度更快的行星吞噬速度，而巨大的行星的发生率相似。我们的方案解释了通过恒星与其伴侣之间的潮汐相互作用，低质量主序列恒星的特殊旋转速度。当前的观察样本太小且不完整，因此不允许我们测试模型。
The method of gyrochronology relates the age of its star to its rotation period. However, recent evidence of deviations from gyrochronology relations was reported in the literature. Here, we study the influence of tidal interaction between a star and its companion on the rotation velocity of the star, in order to explain peculiar stellar rotation velocities. The interaction of a star and its planet is followed using a comprehensive numerical framework that combines tidal friction, magnetic braking, planet migration, and detailed stellar evolution models from the GARSTEC grid. We focus on close-in companions from 1 to 20 M$_{Jup}$ orbiting low-mass, 0.8 and 1 M$_{\odot}$, main-sequence stars with a broad metallicity range from [Fe/H] = -1 to solar. Our simulations suggest that the dynamical interaction between a star and its companion can have different outcomes, which depend on the initial semi-major axis and the mass of the planet, as well as the mass and metallicity of its host star. In most cases, especially in the case of planet engulfment, we find a catastrophic increase in stellar rotation velocity from 1 kms$^{-1}$ to over 40 kms$^{-1}$, while the star is still on the main-sequence. The main prediction of our model is that low-mass main-sequence stars with abnormal rotation velocities should be more common at low-metallicity, as lower [Fe/H] favours faster planet engulfment, provided occurrence rate of close in massive planets is similar at all metallicities. Our scenario explains peculiar rotation velocities of low-mass main-sequence stars by the tidal interaction between the star and its companion. Current observational samples are too small and incomplete, and thus do not allow us to test our model.
