Rotation, differential rotation, and gyrochronology of active Kepler stars
Rotation, differential rotation, and gyrochronology of active Kepler stars
复制标题
活跃开普勒恒星的自转、差分自转和陀螺年代学
DOI：
10.1051/0004-6361/201526216
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
L. Gizon
中科院分区：
文献类型：
--
作者：
T. Reinhold;L. Gizon
CoRoT和开普勒卫星的高精度测光测量了数万颗恒星的表面旋转周期。我们的主要目标是推导出成千上万的场星的年龄使用一致的旋转周期测量在不同的gyrochronology关系。多个旋转周期被解释为表面差异旋转（DR）。我们重新分析了Reinhold等人（2013）的24，124颗开普勒恒星的样本，使用基于Lomb-Scargle周期图的不同方法。每个乳区（Q1-Q14）使用预美白方法单独处理。此外，分析了完整的时间序列及其不同的片段。对于超过18，500颗恒星，我们的结果与McQuillan et al.（2014）的旋转周期一致。其中，超过12，300颗恒星显示出多个显著的峰值，我们将其解释为DR。使用不同的陀螺年代学关系，对超过17，000颗恒星推导出1亿年至10亿年的陀螺年代学年龄。在3200-4700 K之间，Teff的年龄分布为双峰型.导出的年龄揭示了一个经验的活动年龄关系，光度变化作为恒星活动代理。此外，我们还发现了1079颗周期非常稳定（大部分是短周期）的恒星。这些周期的一半可能与非食伴星稳定的自转有关，另一半可能是由于脉动。由于超过93.0%的恒星似乎比太阳年轻，因此导出的陀螺年代学年龄受到很好的限制，其中校准是最可靠的。解释年龄分布中的双峰性是具有挑战性的，并且限制了准确的恒星年龄预测。在超过三年的观测中，存在着自转周期几乎恒定的冷恒星，这可能是因为它们与伴星同步，或者是一种发电机机制保持了斑点的结构非常稳定。
The high-precision photometry from the CoRoT and Kepler satellites has led to measurements of surface rotation periods for tens of thousands of stars. Our main goal is to derive ages of thousands of field stars using consistent rotation period measurements in different gyrochronology relations. Multiple rotation periods are interpreted as surface differential rotation (DR). We re-analyze the sample of 24,124 Kepler stars from Reinhold et al. (2013) using different approaches based on the Lomb-Scargle periodogram. Each quarter (Q1-Q14) is treated individually using a prewhitening approach. Additionally, the full time series, and different segments thereof are analyzed. For more than 18,500 stars our results are consistent with the rotation periods from McQuillan et al. (2014). Thereof, more than 12,300 stars show multiple significant peaks, which we interpret as DR. Gyrochronology ages between 100 Myr and 10 Gyr were derived for more than 17,000 stars using different gyrochronology relations. We find a bimodal age distribution for Teff between 3200-4700 K. The derived ages reveal an empirical activity-age relation using photometric variability as stellar activity proxy. Additionally, we found 1079 stars with extremely stable (mostly short) periods. Half of these periods may be associated with rotation stabilized by non-eclipsing companions, the other half might be due to pulsations. The derived gyrochronology ages are well constrained since more than 93.0 % of the stars seem to be younger than the Sun where calibration is most reliable. Explaining the bimodality in the age distribution is challenging, and limits accurate stellar age predictions. The existence of cool stars with almost constant rotation period over more than three years of observation might be explained by synchronization with stellar companions, or a dynamo mechanism keeping the spot configurations extremely stable.
影响因子：
6.5
作者：
T. Reinhold;A. Reiners;G. Basri
通讯作者：
T. Reinhold;A. Reiners;G. Basri