DIX Planetary Science Seminar

The ongoing Transiting Exoplanet Survey Satellite (TESS) mission is an all-sky survey designed to detect planets around bright, nearby stars by providing high-cadence, precision photometry for hundreds of thousands of targets. TESS is optimized to detect planets around M dwarf stars, and my work focuses on the detection and characterization of such worlds. As the most common stellar type, with strong planet signals in both radial velocity and transit, M dwarf stars are ideal targets for exoplanet searches. But M dwarf transit searches and planet characterization are complicated by stellar activity in their light curves. In this talk, I will describe my research on detecting and characterizing planets orbiting M dwarf stars, particularly in the presence of spot modulation and flares. I will begin by discussing the pre-Main Sequence M dwarf, AU Mic, which exhibits significant variability in its light curve from both spot modulation and flares. These features complicate the transit fits for the two small planets orbiting the star, but by fitting the activity and transits simultaneously it is possible to construct accurate transit models and therefore derive precise planet radii and transit times. I will also discuss the TOI-700 system. TOI-700 is an M2.5 star in the TESS Southern Continuous Viewing Zone, and with two full years of observations, was shown to have four transiting planets. Two of these planets reside in the star's Habitable Zone (TOI-700 e and d) and remain the only two Earth-sized planets in the Habitable Zone of their host star discovered with TESS to date. Efforts are currently underway to obtain precise masses for these planets, to help move them towards becoming well characterized, 3-D worlds.