Photometric techniques for exoplanet detection: the construction and deployment of the KELT-South telescope

Kuhn, Rudolf Bruwer

Photometric techniques for exoplanet detection: the construction and deployment of the KELT-South telescope

Doctoral Thesis

2014

Publisher

University of Cape Town

Department

Department of Astronomy

Faculty

Faculty of Science

Abstract

In this thesis I present the work I performed during the initial construction and deployment of the second telescope in the KELT project and I report the results of the search for transiting exoplanets and variable stars using one of the first commissioning datasets obtained with the telescope. The KELT-South telescope is located in Sutherland, South Africa and construction started in 2008. The telescope has been operating at full capacity since 2010, after two commissioning seasons from late 2008 to early 2010. I developed all the code that allows it to be fully automatic and robotic and over the last 5 years I have been responsible for the observing operations and general maintenance of the telescope. I also developed many other software tools that help with the identification of the exoplanet candidates. The Kilodegree Extremely Little Telescope (KELT) project at present consists of two robotic, wide field, small aperture telescopes that are designed primarily to find transiting exoplanets around bright stars in the magnitude range 8 < V < 11. Transiting planets orbiting bright stars can be studied with intense follow-up programs with relative ease on larger telescopes, making them favourable targets to determine the atmospheric composition of the planet as well as a host of other properties that cannot be obtained from planets orbiting fainter stars. Of the known 1811 (August 2014) exoplanets only 60 are transiting stars with V < 11 and only 16 of those have been found from the southern hemisphere. The discovery of more of these exoplanets will help constrain the theories of formation and evolution of short period, gas giant exoplanets. Data reduction on one of the commissioning datasets was completed in 2012. The dataset spans 46 days and lightcurves for 78297 objects were obtained. I performed a search for periodicities in the lightcurves and found that 1411 stars showed clear signs of variability and these objects were compiled into a catalogue of possible variable stars. 1018 of the catalogue members were not previously known to be variable. I searched for planetary transits and eight possible exoplanet candidates were identified. Photometric follow-up observations of two targets eliminated them as exoplanet candidates, each being a blended eclipsing binary system. The remaining six candidates are awaiting follow-up observations at present. Although the commissioning dataset served primarily to refine the data reduction pipeline and the procedures I used to find variable stars, I have demonstrated that the KELT-South telescope is capable of detecting the kinds of signals required for exoplanet discovery.

Description

Includes bibliographical references.

Keywords

Astronomy

Reference:

Collections

PhD / Doctoral

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