Nine New Spectroscopic Orbits of Nearby M Dwarfs

In order to fully understand the orbital parameter distributions of our nearest low-mass neighbors, it is critical that we identify the nearby M dwarfs in the very shortest period orbits. Multi-epoch spectroscopic surveys provide the only way to accomplish this. Since 2016, we have been conducting a multi-epoch, high-resolution spectroscopic survey of nearby M dwarfs. We present nine new spectroscopic orbits, of which five systems are new discoveries, including a new eclipsing binary system. We measured these orbits using the Tillinghast Reflector Echelle Spectrograph (TRES, R = 44,000) on the 1.5m telescope at the Fred Lawrence Whipple Observatory (FLWO) on Mt. Hopkins, AZ, and the CHIRON spectrograph (R = 80,000) at the Cerro Tololo Inter-American Observatory / Small and Moderate Aperture Research Telescope System (CTIO/SMARTS) 1.5m. The majority of these systems are within 15 pc and have primary masses less than 0.3 solar masses. These systems' orbital parameters include a range of orbital periods (0.6-945 days), mass ratios (0.2-1.0), and eccentricities (circular to 0.72). The addition of these new systems with orbital parameters to the known population of multiple M dwarf systems improves our understanding of the true mass ratio and separation distributions of these low-mass stars. Furthermore, the combination of these systems' gamma velocities with their proper motions and parallaxes permits the exploration of how these systems form and evolve over time. This work was made possible through the support of grants from the National Science Foundation, the National Aeronautics and Space Administration, and the John Templeton Foundation. E.P. is supported by an NSERC Postgraduate Scholarship.