Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory
Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory
复制标题
使用帕拉纳尔天文台 20 厘米 NGTS 望远镜进行闪烁限制光度测量
DOI：
10.1093/mnras/stab3399
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发表时间：
2021
影响因子：
3.5
通讯作者：
Robert West
中科院分区：
文献类型：
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作者：
S. O'Brien;D. Bayliss;J. Osborn;E. Bryant;J. McCormac;P. Wheatley;J. Acton;D. Alves;D. Anderson;M. Burleigh;S. Casewell;S. Gill;M. Goad;B. Henderson;J. Jackman;M. Lendl;R. Tilbrook;S. Udry;J. Vines;Robert West
对明亮恒星的地面测光预计会受到大气闪烁的限制，尽管在实践中观测常常受到其他系统噪声源的限制。我们分析了122个夜晚的明亮星星（G mag（cid：2）11.5）测光使用下一代凌日巡天（NGTS）在智利帕拉纳尔天文台的20厘米望远镜。我们比较噪声特性的理论噪声模型，我们证明NGTS测光明亮的恒星确实是有限的大气闪烁。我们在帕拉纳尔天文台确定了一个中位闪烁系数C Y = 1。54，这是在很好的协议，从湍流廓线测量在天文台以前的结果。我们发现，单独的NGTS望远镜在同时监测同一场时，对闪烁进行了一致的测量。使用同期的气象数据，我们发现，在对流层顶较高的风速与减少长期曝光（t = 10 s）闪烁。因此，6月至8月的冬季为帕拉纳尔天文台提供了对明亮恒星进行高精度测光的最佳条件。这项工作表明，NGTS测光数据，收集搜寻系外行星，其中包含一个记录的闪烁条件在帕拉纳尔。
Ground-based photometry of bright stars is expected to be limited by atmospheric scintillation, although in practice observations are often limited by other sources of systematic noise. We analyse 122 nights of bright star ( G mag (cid:2) 11.5) photometry using the 20-cm telescopes of the Next-Generation Transit Surv e y (NGTS) at the Paranal Observatory in Chile. We compare the noise properties to theoretical noise models and we demonstrate that NGTS photometry of bright stars is indeed limited by atmospheric scintillation. We determine a median scintillation coefficient at the Paranal Observatory of C Y = 1 . 54, which is in good agreement with previous results derived from turbulence profiling measurements at the observatory. We find that separate NGTS telescopes make consistent measurements of scintillation when simultaneously monitoring the same field. Using contemporaneous meteorological data, we find that higher wind speeds at the tropopause correlate with a decrease in long-exposure ( t = 10 s) scintillation. Hence, the winter months between June and August provide the best conditions for high-precision photometry of bright stars at the Paranal Observatory. This work demonstrates that NGTS photometric data, collected for searching for exoplanets, contains within it a record of the scintillation conditions at Paranal.