Dark matter dynamical friction on binary stars in the faintest dwarf galaxies: I. Analytical approach
The study analyzes how binary stars moving through a uniform dark matter background experience dynamical friction, deriving formulas for their orbital evolution. It finds that wide binaries oscillate significantly in eccentricity over Gyr timescales while semi-major axes decrease slowly. Close binaries show increased eccentricity and decreasing semi-major axes. This evolution suggests that unresolved binaries can bias velocity dispersion measurements, potentially allowing them to probe dark matter content in faint dwarf galaxies.