2022 • 2022PhDT.........6C
Abstract • The M dwarfs have become primary targets for the detection and characterization of habitable, Earth-sized exoplanets due to their small sizes, their low temperatures, and their abundance in the Solar neighborhood. However, unknown stellar multiplicity can inhibit planet detection and lead to obstacles in planet characterization, and stellar companions can hinder planet formation and/or the long-term stability of any inner planets that they host. Fortunately, speckle interferometry has become a leading technique to search for unknown stellar companions, and to investigate the region around candidate exoplanet hosts. We therefore used speckle interferometry to explore the multiplicity of both planet-hosting and non-planet-hosting M dwarfs. These multiplicity measurements revealed a dearth of close-in stellar companions to M-dwarf TESS Objects of Interest, a new stellar companion to an F1V star, and 26 new companions to nearby field M dwarfs. Additionally, we present a next-generation speckle camera that is optimized for investigating low-mass pairs. These studies have generated two main conclusions: (1) the stellar companions that planet-hosting M dwarfs host differ from those that non-planet-hosting M dwarfs host, and (2) recent advances in speckle interferometry have made speckle cameras substantially more sensitive than in the past, allowing us to probe novel M-dwarf discovery space.