Extended Data Fig. 5: Corner plot diagram for the bombardment parameters of a 2-flux history.

The scenario is similar to that reported in Fig. 4, except that both bombardments (β, γ) are “post-accretion” events with onset dates (t_o) explored as free parameters by the MCMC algorithm. Each distribution reflects 10⁶ Markov chain steps and black lines trace the median values (M) of each parameter. Impactor flux β begins with a median onset date of M(t_oβ) ~ 10 My_ss and is intense/brief (M (F_oβ) > 1000 My⁻¹, M(τβ) ~ 10 My). Impactor flux γ begins far later (M(t_oγ) ~ 100 My_ss) but is mild/protracted (M(F_oγ) ~ 1 My⁻¹, M(τγ) ~ 500 My), similar to the primordial flux in Fig. 4b. There is little apparent correlation between fluxes, but within each flux, F_o scales inversely with longer τ and later t_o. See Fig. 4 caption for description of corner plot layout. Extended Data Table 2 reports summary statistics.