Rotation period distributions in the Eunomia (a), Hungaria (b), and Vesta (c) families. Periods are from B. D. Warner et al. (2021) and Gaia DR3 photometry. Data with quality code U ﹩\lt ﹩ 2– are excluded from the plots. The solid curves, produced by fitting a bimodal Gaussian function to the data, serve to highlight the short-period and long-period populations within each family. The dashed vertical lines define the bifurcation discussed in Section 5. Note the clear bifurcation of periods for Hungaria family asteroids.