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Title: Analysis and optimisation of ground based transiting exoplanet surveys
Author: Walker, Simon R.
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2013
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One of the most surprising aspects of the exoplanet population is the existence of Jupiter sized planets orbiting close to their parent stars. It is currently uncertain how these planets reached such small separations, and they are thought to be markers for the dominant migration mechanism. The Wide Angle Search for Planets (WASP) project is ideally suited for studying these planets, as it has detected the largest number of hot Jupiters to date. I have inverted the observed sample of WASP planets to calculate the underlying population of hot Jupiters through a quantitative study of the selection biases in the WASP project. To achieve this, I synthesised transiting systems and inserted them into WASP data to calculate the probability of detection. The observed population ofWASP planets is then corrected through application of this probability to determine the underlying population. I find a clear pile up in the underlying population at orbital periods between 3 to 5 days, and apply a joint constraint with the underlying population measurement from the Kepler project to propose a new model for the underlying population of giant planets. I propose a model consisting of a rising power law win period with index 1:0 - 0:3, with a Gaussian excess at 3:7 - 0:1 days to model the period pile up. The observed period pile up places crucial constraints on models of hot Jupiter migration. The Next Generation Transit Survey (NGTS) is a new transiting exoplanet survey designed to find Neptunes and super Earths around nearby stars. These stars will be bright, allowing the characterisation of the bulk densities and atmospheric compositions by current and next generation instruments. These planets are numerous but they cause shallow transits, so we must achieve a higher level of precision than has been previously achieved by a wide angle ground based survey. To test the design characteristics and that the required high levels of precision would be achieved, prototype instruments were constructed on La Palma and Geneva. We found that we were able to reach < 0:1% precision on an ensemble of bright stars on the typical transit timescales, indicating that the instrument will be capable of detecting smaller planets. We use Monte Carlo simulations coupled with a detectability analysis to predict that NGTS will detect 200 Neptunes and 30 super Earths with the next generation instrument ESPRESSO.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QB Astronomy