NGTS clusters survey. I. Rotation in the young benchmark open cluster Blanco 1
Edward Gillen, Joshua T. Briegal, Simon T. Hodgkin, Daniel Foreman-Mackey, Floor Van Leeuwen, James A. G. Jackman, James McCormac, Richard G. West, Didier Quelo… 展开作者
Edward Gillen, Joshua T. Briegal, Simon T. Hodgkin, Daniel Foreman-Mackey, Floor Van Leeuwen, James A. G. Jackman, James McCormac, Richard G. West, Didier Queloz, Daniel Bayliss, Michael R. Goad, Christopher A. Watson, Peter J. Wheatley, Claudia Belardi, Matthew R. Burleigh, Sarah L. Casewell, James S. Jenkins, Liam Raynard, Alexis M. S. Smith, Rosanna H. Tilbrook, Jose I. Vines
备注：
19 pages, 14 figures, 2 tables, accepted for publication in MNRAS
我们使用下一代凌日巡天（NGTS）的200天光度监测，确定了1.15亿年前的布兰科1疏散星团中127颗恒星的自转周期。这些恒星跨越F5-M3光谱类型（1.2 $\gtrsim M \gtrsim$ 0.3 M $_{\odot}$），并将布兰科1的已知旋转周期增加了四倍。我们确定旋转周期使用三种方法：高斯过程（GP）回归，广义自相关（G-ACF）和Lomb-Scargle（LS）周期图，并发现GP和G-ACF更适用于不断发展的斑点调制模式。在中F和中K光谱类型之间，单颗恒星遵循一个明确的旋转序列，从2到10天，而在光度多系统中的恒星通常旋转得更快。这可能表明，一个中等到高质量比的伴星的存在抑制了早期前主序期间的角动量损失机制，并且这个特征在~ 1亿年时没有被抹去。大多数中F到中K星显示不断变化的调制模式，而大多数M星显示稳定的调制信号。这种形态上的变化与从一个定义明确的旋转序列（中F到中K星）到一个广泛的旋转周期分布（晚K和M星）的转变相吻合。最后，我们比较了我们对Blanco 1和类似年龄的昂宿星团的旋转结果：两个星团中的单恒星种群具有一致的旋转周期分布，这表明恒星的角动量演化遵循一个明确的路径，至少对于中F到中K恒星来说，强烈的印记是~ 1亿年。
英文摘要：
We determine rotation periods for 127 stars in the ~115 Myr old Blanco 1 open cluster using ~200 days of photometric monitoring with the Next Generation Transit Survey (NGTS). These stars span F5-M3 spectral types (1.2 $\gtrsim M \gtrsim$ 0.3 M$_{\odot}$) and increase the number of known rotation periods in Blanco 1 by a factor of four. We determine rotation periods using three methods: Gaussian process (GP) regression, generalised autocorrelation (G-ACF) and Lomb-Scargle (LS) periodograms, and find that GPs and G-ACF are more applicable to evolving spot modulation patterns. Between mid-F and mid-K spectral types, single stars follow a well-defined rotation sequence from ~2 to 10 days, whereas stars in photometric multiple systems typically rotate faster. This may suggest that the presence of a moderate-to-high mass ratio companion inhibits angular momentum loss mechanisms during the early pre-main sequence, and this signature has not been erased at ~100 Myr. The majority of mid-F to mid-K stars display evolving modulation patterns, whereas most M stars show stable modulation signals. This morphological change coincides with the shift from a well-defined rotation sequence (mid-F to mid-K stars) to a broad rotation period distribution (late-K and M stars). Finally, we compare our rotation results for Blanco 1 to the similarly-aged Pleiades: the single star populations in both clusters possess consistent rotation period distributions, which suggests that the angular momentum evolution of stars follows a well-defined pathway that is, at least for mid-F to mid-K stars, strongly imprinted by ~100 Myr.
NGTS clusters survey - VII. An Enigmatic Short-Period Circumsecondary Disk Candidate in Orion
Queen’s University Belfast（贝尔法斯特女王大学）；Queen Mary University of London（伦敦大学玛丽女王学院）；Leiden University（莱顿大学）；Ludwig-Maximilians-Universität München（慕尼黑路德维希-马克西米利安大学）；Universidad Católica del Norte（北方天主教大学）；University of Warwick（华威大学）；University of Leicester（莱斯特大学）；University of California Irvine（加州大学尔湾分校）；University of Sheffield（谢菲尔德大学）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Observatoire de Paris（巴黎天文台）；Université Paris-Saclay（巴黎萨克雷大学）；Université de Liège（列日大学）；Rugby School（拉格比学校）；Massachusetts Institute of Technology（麻省理工学院）；Universidad Diego Portales（迭戈·波特莱斯大学）；South African Astronomical Observatory（南非天文台）；Keele University（基尔大学）；University of Birmingham（伯明翰大学）
The Longest-period Young Transiting Exoplanets. A Duo of Puffy Giants inside a Debris Disk
Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de la Laguna（拉古纳大学）；European Space Agency (ESA)（欧洲空间局）；Academia Sinica Institute of Astronomy and Astrophysics（中央研究院天文及天文物理研究所）；University of Warwick（华威大学）
