Know thy star, know thy planet – disentangling planet discovery & stellar activity

Diplôme Thèse Know thy star, know thy planet – disentangling planet discovery & stellar activity eng 2019-06-26 author Giles Helen 843538 director Lovis Christophe 134919 director Udry Stéphane 23409 10.13097/archive-ouverte/unige:123850 urn:nbn:ch:unige-1238506 Sc. 5377 Kepler and K2 have enabled studies of exoplanets and stars. This thesis focuses on two goals: characterising starspots on Kepler stars and finding and following up K2 exoplanets. Starspot evolution produces quasi-sinusoidal light curves. Fitting ACFs with periodic functions, I found a correlation between starspot size, decay lifetime and stellar effective temperature. This method is used as part of RV follow-up for planet-hosting stars. K2 light curves were analysed using a new pipeline. This generated two confirmed planets: K2-140b, a Jupiter-like planet orbiting in 6.57 days (the 9th hot Jupiter from K2) and K2-311b, a single-transit-event lasting 54 hours. With RV follow-up and tools, this Jupiter-sized planet orbits in ~10 years. This is currently the longest-period transiting planet discovered. This thesis contributes to future exoplanet endeavours to discover smaller planets in distant orbits, by providing techniques for exoplanet follow-up and improving our knowledge and understanding of stellar activity. Astrophysics Astronomy Exoplanets Planets Extrasolar Planets Transits Stars Starspots Starspot Decay Kepler K2 Photometry Light Curves Dewey 520 Swiss National Science Foundation NCCR PlanetS CH 26 Département d'astronomie 12 false 7e34d3a6-257c-4691-83ad-404a9e851da4 Thesis Public Thesis_HelenGiles-1.pdf 24517160 application/pdf openAccess Faculté des sciences / Département d'astronomie

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Giles, Helen