The POKEMON Speckle Survey of Nearby M dwarfs. III. The Stellar Multiplicity Rate of M Dwarfs Within 15 pc

M dwarfs are ubiquitous in our galaxy, and the rate at which they host stellar companions, and the10 properties of these companions, provides a window into the formation and evolution of the star(s),11 and of any planets that they may host. The Pervasive Overview of ‘Kompanions’ of Every M dwarf12 in Our Neighborhood (POKEMON) speckle survey of nearby M dwarfs is volume-limited from M0V13 through M9V out to 15 parsecs, with additional targets at larger distances. In total, 1124 stars were14 observed, and 454 of these are within the volume-limited, 15-pc sample of M-dwarf primaries. When15 we combine the speckle observations with known companions from the literature, we find that the16 stellar multiplicity rate of M dwarfs within 15 parsecs is 24.7 ± 2.0%, and that the companion rate17 is 29.5 ± 2.1%. We also find that the projected separation distribution for multiples that are known18 to host planets peaks at 305 au, while the distribution for multiples that are not yet known to host19 planets peaks at 12.1 au. This result suggests that the presence of close-in stellar companions inhibits20 the formation of planetary systems in M dwarfs, similar to what has been found for FGK stars