Fig. 5. Occurrence timescale (solid lines) and cumulative number (dashed lines) of ‘Oumuamua’s cohorts within d of the Sun for travel distances in the ISM L = 1 pc, 10 pc, 100 pc (increasing line widths). The timescale of occurrence of a light sail grows with increasing traveling distance, L, as a result of diffusion in the interstellar space. The timescale of occurrence within 100 au is insensitive to the travel distance, L, when L > 10 pc. The unshaded region is the observational domain of the first ∼10 yr of the Vera C. Rubin telescope.