The Detection and Characterization of Planets Around M Dwarf Stars

M dwarfs are the most abundant stellar type in our galaxy and the most common type of exoplanet host star. The ongoing Transiting Exoplanet Survey Satellite (TESS) mission is an all-sky mission designed to detect planets around nearby, bright stars. With its high-cadence, high-precision photometry, TESS has revolutionized the study of stellar activity of low mass stars. I will present my work on the detection and characterization of planets orbiting low mass stars. First, I will discuss the discovery of the TOI-700 planets, including TOI-700 d, the first Habitable Zone, Earth-sized planet discovered with TESS. I will describe our collaboration’s ongoing work to further characterize this system. Next, I will discuss my research characterizing the pre-Main Sequence M dwarf, AU Mic. AU Mic exhibits significant variability in its light curve in the form of spot modulation and flares. Both of these features complicate the transit fits for AU Mic b and c, but by fitting the activity and transits simultaneously, I am able to construct accurate transit models, and therefore derive precise planet radii. As a part of this work, I also model the spots and white light flare to study the activity from AU Mic, and I demonstrate the value of TESS 20-second cadence data for modeling flares and transits. Finally, I model the optical flares of Proxima Centauri observed by TESS in order to conduct a transit search across the entire Habitable Zone of the star. While no transiting planets are detected, my flare removal increases the transit sensitivity by 60%. This method has great potential for searching active M dwarf stars observed by TESS to identify small planets that may be masked by stellar flares.