A 4 Gyr M-dwarf Gyrochrone from CFHT/MegaPrime Monitoring of the Open Cluster M67
A 4 Gyr M-dwarf Gyrochrone from CFHT/MegaPrime Monitoring of the Open Cluster M67
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DOI：
10.3847/1538-4357/ac90be
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Ryan Dungee;J. V. van Saders;E. Gaidos;M. Chun;R. García;E. Magnier;S. Mathur;Ângela R. G. Santos
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作者：
Ryan Dungee;J. V. van Saders;E. Gaidos;M. Chun;R. García;E. Magnier;S. Mathur;Ângela R. G. Santos
我们提出了4 Gyr老疏散星团M67的晚期K矮星和早期m矮星成员的恒星旋转周期，作为自转年代学和恒星自旋下降模型测试的校准器。我们利用盖亚EDR3天体测量法进行星团归属，利用Pan-STARRS （PS1）光度法进行双星识别，利用加拿大-法国-夏威夷望远镜的MegaPrime宽视场成像仪对M67进行监测，建立了这组旋转周期。我们确定了M67的1807个成员，其中294个是候选的单个成员，具有显著的旋转周期检测。此外，我们拟合了一个多项式到我们的数据中观察到的周期与颜色衍生的有效温度序列。我们发现非常冷的矮星的旋转可以用简单的固体自旋下降2.7到4 Gyr来解释。我们将这一旋转序列与陀螺年代模型的预测结果进行了比较，发现与Ruprecht 147序列最匹配的是skumich -like spin-down， P = P = 0.62。这表明，对于金属丰度接近太阳的光谱型K7-M0，一旦一颗恒星重新开始旋转，一个简单的类似斯库曼尼的关系就足以描述它们的旋转演化，至少在M67的年龄。此外，对于M1-M3范围内的恒星，我们的数据显示，自旋下降一定在M67年龄之前就已经恢复了，这与最新的自旋下降模型的预测相冲突。
We present stellar rotation periods for late K- and early M-dwarf members of the 4 Gyr old open cluster M67 as calibrators for gyrochronology and tests of stellar spin-down models. Using Gaia EDR3 astrometry for cluster membership and Pan-STARRS (PS1) photometry for binary identification, we build this set of rotation periods from a campaign of monitoring M67 with the Canada–France–Hawaii Telescope’s MegaPrime wide-field imager. We identify 1807 members of M67, of which 294 are candidate single members with significant rotation period detections. Moreover, we fit a polynomial to the period versus color-derived effective temperature sequence observed in our data. We find that the rotation of very cool dwarfs can be explained by simple solid-body spin-down between 2.7 and 4 Gyr. We compare this rotational sequence to the predictions of gyrochronological models and find that the best match is Skumanich-like spin-down, P rot ∝ t 0.62, applied to the sequence of Ruprecht 147. This suggests that, for spectral types K7–M0 with near-solar metallicity, once a star resumes spinning down, a simple Skumanich-like relation is sufficient to describe their rotation evolution, at least through the age of M67. Additionally, for stars in the range M1–M3, our data show that spin-down must have resumed prior to the age of M67, in conflict with the predictions of the latest spin-down models.