Collaborative Research: Exploring the Nearest Stars on Solar System Scales

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This project will explore the environments of more than 2000 of the nearest star systems to the Sun. The objectives are to (a) discover how unusual our Sun is in its stellar solitude, (b) understand how many stars of different types are multiples, (c) provide fundamental statistics that will drive our knowledge of how stars form, and (d) provide a list of stars where analogues of our Solar System might be found. The project allows us to place our own Sun in context in our Galaxy, answering the broad question, "How does our Sun compare to other stars?" It will also provide important information about the likelihood of habitable worlds. The project provides opportunities for graduate and undergraduate student training at both institutions, each of which includes significant fractions of minority students. Both institutions will develop supplemental observing programs for students and general public using local facilities, and they will integrate these with their educational programs.Two high-resolution imaging surveys will be completed using the Differential Speckle Survey Instrument (DSSI), a unique speckle imaging system that provides diffraction-limited imaging in two colors simultaneously. Observations will primarily be taken at Lowell Observatory's 4.3-meter Discovery Channel Telescope and at the Gemini North 8.1-meter Telescope. The first survey will target more than 1500 stars within 25 parsecs with V magnitudes brighter than 16. Observing nearby stars with DSSI will enable mapping of their stellar environments down to separations smaller than the distance of Mercury to the Sun, even at the horizon of the sample. The results will provide crucial insight into the star formation process, and the statistics of stellar multiplicity will be the benchmark for other types of multiplicity studies, with an emphasis on the Solar System scales crucial for planet formation. The second survey will target more than a thousand K-dwarfs within 50 parsecs in an equatorial sample that can be observed from both the northern and southern hemispheres. Incorporating other techniques together with DSSI images, these stars will be surveyed for companions down to Jovian masses to provide a unique data set of companions spanning a mass range of 1000 for this specific spectral type, providing a legacy data set that can be referenced for decades to come.