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

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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.