论文标题
K2广告系列0-18的恒星轮换期 - 旋转期双峰性和同时可变性的证据降低
Stellar rotation periods from K2 Campaigns 0-18 -- Evidence for rotation period bimodality and simultaneous variability decrease
论文作者
论文摘要
通过开普勒任务观察到的恒星的旋转周期测量表明，在中间旋转期间缺乏恒星，并伴随着光度变异性的降低。无论是所谓的缺乏区域是开普勒场中恒星的特殊性，还是反映了恒星磁活动的一般表现，仍在争论中。我们的目标是测量数以万计的K2恒星的恒星旋转周期和光度变化，沿着沿着黄道平面的不同磁场，以阐明恒星旋转和光度变化之间的关系。我们使用Lomb-Scargle期间图，自动相关和小波函数来确定一致的旋转周期。通过计算光曲线的变异范围来评估恒星亮度的可变性。我们进一步应用高斯混合模型在旋转期分布中搜索双峰性。结合了所有K2广告系列的测量值，我们检测到29,860颗恒星的旋转周期。对于低于6000K的有效温度，可变性范围显示在不同时期的局部最小值，与750 Myr的等速线酮一致。此外，K2旋转周期分布显示了双峰性的证据，尽管与开普勒场相比，缺乏区域不太明显。双峰分布浸入时的时期与该期间的局部变异性最低符合良好的一致性。我们得出的结论是，双峰时期存在于天空的不同田间，因此是恒星磁性活性的一般体现。缺乏区域的变异性降低被解释为在黑点和明亮的面前的取消。我们的结果强烈建议，到目前为止，Faculae的作用已经被低估了，这表明对旋转期的亮度变异性具有更复杂的依赖性。
Rotation period measurements of stars observed with the Kepler mission have revealed a lack of stars at intermediate rotation periods, accompanied by a decrease of photometric variability. Whether this so-called dearth region is a peculiarity of stars in the Kepler field, or reflects a general manifestation of stellar magnetic activity, is still under debate. Our goal is to measure stellar rotation periods and photometric variabilities for tens of thousands of K2 stars, located in different fields along the ecliptic plane, to shed light on the relation between stellar rotation and photometric variability. We use Lomb-Scargle periodograms, auto-correlation and wavelet functions to determine consistent rotation periods. Stellar brightness variability is assessed by computing the variability range from the light curve. We further apply Gaussian mixture models to search for bimodality in the rotation period distribution. Combining measurements from all K2 campaigns, we detect rotation periods in 29,860 stars. For effective temperatures below 6000K, the variability range shows a local minimum at different periods, consistent with an isochrone age of 750 Myr. Additionally, the K2 rotation period distribution shows evidence for bimodality, although the dearth region is less pronounced compared to the Kepler field. The period at the dip of the bimodal distribution shows good agreement with the period at the local variability minimum. We conclude that the period bimodality is present in different fields of the sky, and is hence a general manifestation of stellar magnetic activity. The reduced variability in the dearth region is interpreted as a cancelation between dark spots and bright faculae. Our results strongly advocate that the role of faculae has been underestimated so far, suggesting a more complex dependence of the brightness variability on the rotation period.
