Data mining the Next Generation Transit Survey for exoplanet systems around dead stars

下一代过境调查（NGTS）是世界上最敏感的地面项目，寻找其他恒星周围的太阳系外行星。它位于欧洲南方天文台的帕拉纳尔站，这是南半球天文观测的最佳地点。每天晚上，NGTS的12个20厘米机器人望远镜通过每10秒拍摄一张96平方度的图像来监视数十万颗恒星，以寻找当行星经过其宿主星星前面时发生的光下降，就像我们从地球上看到的那样。自2016年初开始调查以来，NGTS已经获得了超过1000亿次单独的光度测量。如此庞大的数据量需要大量的计算工作来清理和校准图像，然后通过定制设计的算法自动搜索系外行星的特征。NGTS到目前为止已经发现了15颗新行星，它们都围绕着像太阳这样的恒星。但是NGTS监测许多类型的恒星，我们现在希望搜索一些更奇特的星星类型，以发现它们是否也是行星系统的宿主。关键目标/目的：在银河系中所有类型的孤立恒星中，有一个显著的差异，即没有发现行星，白色矮星。97%的恒星，包括我们的太阳，将以恒星残余物的形式结束生命，冷却，称为白色矮星。围绕这些恒星的行星系统的命运是未知的。当主序星星星膨胀成红巨星时，离母星星最近的行星预计会被吞噬，而那些离母恒星更远的行星预计会在达到白色矮星阶段后保持完整。越来越多的证据表明，这些行星系统在某种程度上确实存在。白色矮星大气层的污染，以及星周尘埃和富含金属的气体盘，都已经被观察到，只能用一个离星星太近的岩石体的破裂来解释。甚至有一个系统正在积极监测这种解体过程。该项目的目的是挖掘NGTS数据档案，以寻找白色矮星周围行星和小行星的证据。就其性质而言，这些恒星是NGTS所能探测到的最微弱的恒星之一，而且相对罕见。因此，学生需要开发专业技术和软件来提取和分析这些特定恒星的数据。

Description:The Next Generation Transit Survey(NGTS) is the world's most sensitive ground-based project searching for extra-solar planets around other stars. It is situated at the European Southern Observatory's Paranal station, the best site for astronomical observations in the southern hemisphere. Each night, NGTS's twelve 20 cm robotic telescopes monitor hundreds of thousands of stars by taking an image of a 96 square degree field every 10 seconds, to find the tell-tale drop in light that happens as a planet passes in front of its host star, as seen in our line of sight from Earth. Since it began its survey in early 2016, NGTS has obtained more than 100 billion individual photometric measurements. This volume of data requires a significant computing effort to both clean and calibrate the images, and then automatically search for the signatures of exoplanets through custom-designed algorithms.NGTS has discovered 15 new planets so far, all of them around stars like the Sun. But NGTS monitors many kinds of stars, and we now wish to search some of the more exotic types of star to discover whether they too are hosts of planetary systems.Key Objectives/Aims:Of all the types of isolated stars in the galaxy there is one signficant discrepancy where no planets have been detected, White Dwarfs. 97 percent of stars, including our own Sun, will end their life as the remnant, cooling, cores of stars, known as White Dwarfs. The fate of the planetary systems around these stars is unknown. Planets closest to the parent star are expected to be destroyed as they are engulfed when a main sequence star expands to a red giant, but those further out are expected to remain intact once the White Dwarf stage has been reached. And there is growing evidence that these planetary systems do survive to some extent. Contamination of the white dwarfs' atmospheres, as well as circumstellar dust and metal rich gas discs, have all been observed, and can only be explained by the disruption of a rocky body that strayed too close to the star. There is even one system where such a disintegration process is being actively monitored. The aim of this project is to mine the NGTS data archive for the evidence of planets and asteroids around White Dwarf stars. By their nature, these stars are some of the faintest that NGTS can detect, and are relatively rare. Thus, the student will need to develop specialist techniques and software to extract and analyse the data for these specific stars.