Diffusion timescales in fiducial R_c = 60 km bodies’ interiors, for different chondritic compositions. EH and OC lines are mostly overlapping. Solid lines are bodies with intact matrices (K = 10⁻¹⁷m²), while dashed lines are fractured bodies (K = 10⁻¹³ m²). Dashed–dotted lines are EH and OC bodies if they had the same grain size as CCs, d = 1 μm. The shaded region denotes timescales relevant for planetesimal thermal evolution.