Finding transiting exoplanets with NGTS

下一代凌日巡天（NGTS）是一个基于地面的项目，目的是寻找凌日宿主恒星的太阳系外行星。它的主要目标是寻找海王星大小的行星，也许是围绕恒星的最大的岩石行星（“超级地球”），这些行星也足够明亮，可以进行后续研究，以确定它们的质量和密度，并调查行星的大气成分，例如即将到来的詹姆斯韦伯太空望远镜（JWST）。NGTS天文台由12个20厘米的望远镜组成，共同提供96平方度的广阔视野。每台望远镜都配备了一个“深度耗尽”CCD相机，该相机对红光波长最敏感，是最大限度地发现小半径行星围绕低质量冷恒星运行的理想选择。NGTS的光度精度达到0.1%，比以前的地面凌日巡天提高了10倍。NGTS望远镜位于欧洲南方天文台位于智利帕拉纳尔的主站，那里是著名的VLT的所在地。2016年初开始全面运营。在大约100天到9个月的时间里，NGTS每晚都会对数百万颗恒星进行监测。目前，NGTS已经积累了数百tb的数据和数百万张图像，这些数据必须由复杂的算法和定制软件自动搜索。NGTS已经发现了大约25颗新的系外行星。在莱斯特大学，我们正在领导对NGTS系外行星候选者的光度跟踪研究。在从自动算法突出显示的数千条光曲线中仔细选择目标后，我们使用南非天文台的望远镜来确认真正的凌日，识别背景双星等模拟物，并改进轨道周期。莱斯特的NGTS团队希望吸引一位热情的博士生参与到这些令人兴奋的系外行星发现的工作中来。一旦新的系外行星被确认，学生将有机会通过分析凌日的光度测定和径向速度观测来测量它们的质量，从而对其中一些行星进行表征。NGTS望远镜还用于学生有机会参与的几个更令人兴奋的系外行星项目。例如，我们使用NGTS数据来确认美国宇航局TESS卫星发现的系外行星，提供额外的长期数据来完善它们的轨道周期和星历，寻找只被TESS观测过一次的长周期行星，并在疏散星团中寻找非常年轻的行星。所有这些项目都对NGTS联盟的任何成员开放。最后，在它的调查数据中，NGTS还收集了大量不同类型的变星和其他天体的长期、高节奏的观测数据。我们特别鼓励博士生利用这些非系外行星的数据，例如，通过搜索和研究非常低质量的红矮星双星，以及其他罕见类型的双星。有关NGTS计划的详情，请浏览我们的网页http://ngtransits.org/index.html

The Next Generation Transit Survey (NGTS) is a ground-based project to search for extra-solar planets transiting their host stars. Its primary goal is to find Neptune-sized planets, and perhaps the largest rocky planets ("Super-Earths") around stars that are also bright enough to enable follow-up studies to determine their masses and densities, and to investigate the planets' atmospheric compositions, for example with the forthcoming James Webb Space Telescope (JWST). The NGTS observatory consists of twelve 20cm telescopes working together to provide a wide 96 square degree field of view. Each telescope is equipped with a "deep depleted" CCD Camera that is most sensitive at red optical wavelengths, ideal for maximising the probability of finding small radius planets orbiting low mass, cool stars. NGTS achieves a photometric precision of 0.1%, a factor 10 improvement on previous ground-based transit surveys. The NGTS telescopes are located at the European Southern Observatory's primary station at Paranal, Chile, the home of the famous VLT. Full operations began in early 2016. Millions of stars are monitored nightly by NGTS for between ~100 days and nine months. Already, NGTS has accumulated several hundred Terabytes of data, and millions of images, that have to be searched automatically by sophisticated algorithms and bespoke software. NGTS has already discovered around 25 new exoplanets. At Leicester, we are leading the photometric follow-up of NGTS exoplanet candidates. After carefully selecting targets from among thousands of light curves highlighted by the automatic algorithms, we use telescopes at the South African Astronomical Observatory to confirm bona fide transits, identify mimics such as background binary stars, and to refine the orbital periods. The NGTS team at Leicester would like to attract an enthusiastic PhD student to participate in the work leading to these exciting exoplanet discoveries. Once new exoplanets have been confirmed, the student will have the opportunity to work on characterising some of them through analysing photometry of the transits and radial velocity observations to measure their masses.The NGTS telescopes are also used for several more exciting exoplanet projects that a student has the opportunity to participate in. For example, we use NGTS data to confirm exoplanet discoveries from NASA's TESS satellite, provide additional long term data to refine their orbital periods and ephemerises, hunt for long period planets which have only been seen to transit once by TESS, and to search for very young planets in open clusters. All of these projects are open for any member of the NGTS consortium to join. Finally, in its survey data NGTS is also gathering long term, high cadence, observations of a host of different types of variable stars and other celestial objects. We would particularly encourage a PhD student to exploit some of these non-exoplanet data, for example by searching for and studying eclipsing very low mass red dwarf binaries, and other rare types of binary stars.Further details of the NGTS project can be found on our website http://ngtransits.org/index.html