Abstracts Astronomy & Space Science

In Search of Small Planets Around Small Stars: Conducting Photometric Transit Surveys of Nearby M-dwarfs

by Dax https://orcid.org/0000-0002-2457-7889 Feliz

M-dwarfs have the lowest mass, size, luminosity and temperature of main sequence stars and also make up the majority of the total number of stars in our Milky Way galaxy. However, since the first exoplanet systems that were discovered in the 1990s the majority of planet discoveries have been around Sun-like stars. In recent years, the search for exoplanets around M-dwarfs has expanded steadily although these types of stars remain largely under-surveyed for planetary eclipses. This dissertation presents the results of three studies investigating nearby M-dwarfs with a particular focus on whether these M-dwarfs harbor planetary systems. For the first project, we present the analysis of an extensive photometric monitoring campaign of the nearest M-dwarf star, Proxima Centauri, using ground-based telescopes around the globe with observations spanning from 2006–2017. For the second project, we continued our analysis of our ground-based observations of Proxima Centauri to explore if any planetary eclipses of the planet Proxima Centauri b could be detected in the period range of 1–30 days. For the third project, we present an analysis of 33,054 M-dwarf stars, located within 100 parsecs, via observations from the Transiting Exoplanet Survey Satellite (TESS). We present a new pipeline called NEMESIS, developed to extract detrended photometry from the TESS full frame images (FFIs) and to perform transit searches of single-sector data in TESS FFIs for sectors 1–5. In this work, we detect 183 threshold crossing events, and present 29 candidate planets for sectors 1 5, 24 of which are new detections that are unreported by the TESS mission. The results from this project provide a framework to conduct all-sky transit surveys from the prime TESS mission and potentially produce a yield of hundreds of planet candidates that transit nearby M-dwarf host stars.