Program: GS-2019A-Q-302

We propose to use 'Alopeke and the Differential Speckle Survey Instrument (DSSI) on Gemini-North and -South to complete our survey of ~1000 of the nearest M dwarfs to reveal stellar companions at separations on Solar System scales. DSSI on Gemini is able to detect companions with separations smaller than the Sun to Mercury for stars out to 25 pc. The resulting portrait of single, binary, triple, and higher order multiple star systems will drive research on star formation processes for most stars in the Galaxy, while individual measurements of companion locations and types will be used as benchmarks for decades. Ultimately, we will answer the basic questions of whether or not most stars are single or multiple, by how much the multiplicity changes with stellar mass, and which stars orbit one another in such configurations that make difficult the creation of planets.