Stellar Rotation in the K2 Sample: Evidence for Modified Spin-down
Stellar Rotation in the K2 Sample: Evidence for Modified Spin-down
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DOI：
10.3847/1538-4357/abf63e
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发表时间：
2021-01
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通讯作者：
Tyler A. Gordon;J. Davenport;R. Angus;D. Foreman-Mackey;E. Agol;K. Covey;M. Agüeros;D. Kipping
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作者：
Tyler A. Gordon;J. Davenport;R. Angus;D. Foreman-Mackey;E. Agol;K. Covey;M. Agüeros;D. Kipping
利用拟周期核函数高斯过程模型分析了284,834个唯一K2目标的光曲线。通过将K2恒星与盖亚数据发布2号的观测结果交叉匹配，我们已经确定了69,627颗可能的主序星。我们从中选取了主序星上8977颗恒星的子样本，并进行了高精度的旋转周期测量。通过这个样本，我们恢复了McQuillan等人首次报道的旋转周期-颜色图中的间隙。虽然这个缺口在Reinhold & Hekker中被初步探测到，但这项工作代表了对K2数据中野星缺口的首次可靠探测。这一点很重要，因为K2在宽角距离下沿着多条视线观测，而开普勒只有一条视线。结合最近关于疏散星团旋转的结果，我们将这一差距解释为偏离t−1/2 Skumanich自旋向下定律的证据，而不是双峰恒星形成历史的指示。我们为样本中284,834颗恒星中的每一颗恒星提供了准周期光曲线模型所有参数的最大似然估计和不确定性。
We analyze light curves of 284,834 unique K2 targets using a Gaussian process model with a quasi-periodic kernel function. By cross-matching K2 stars to observations from Gaia Data Release 2, we have identified 69,627 likely main-sequence stars. From these we select a subsample of 8977 stars on the main sequence with highly precise rotation period measurements. With this sample we recover the gap in the rotation period−color diagram first reported by McQuillan et al. While the gap was tentatively detected in Reinhold & Hekker, this work represents the first robust detection of the gap in K2 data for field stars. This is significant because K2 observed along many lines of sight at wide angular separation, in contrast to Kepler’s single line of sight. Together with recent results for rotation in open clusters, we interpret this gap as evidence for a departure from the t −1/2 Skumanich spin-down law, rather than an indication of a bimodal star formation history. We provide maximum likelihood estimates and uncertainties for all parameters of the quasi-periodic light-curve model for each of the 284,834 stars in our sample.