Spectroscopic Orbits of Exoplanet Host Binaries

We propose to obtain NEID & CHIRON spectra of close binary stars found to host exoplanets in order to measure the stellar radial velocities. We will combine these velocities with precision astrometry to determine the combined spectroscopic and visual orbit for each system. Our goal is to compare the orbital demographics of exoplanet host binaries to the predictions of numerical simulations and test the dynamical environments where planets can safely form. These simulations show that the presence of a close stellar companion can impact planet formation through dynamical and tidal interactions, such as truncation of the protoplanetary disk and the migration of giant planets. Because 50% of solar-type exoplanet host stars were found to have a stellar companion, this study will provide an important step towards understanding the role of multiplicity in planet formation, evolution, and habitability.